Name: Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope (Video) | JoVE Journal
Uploaded: 2019-03-24T14:00:00.000+00:00
Duration: 9 min 6 s
Description: Learn to visualize antiferromagnetic domains in Fe1+yTe using uniaxial strain and spin-polarized scanning tunneling microscopy. This technique enables precise manipulation of structural domains in superconductors.

ai_agent_IP

ai_agent

maintenance

instantTrialDurationMinutes

isBiopharma

enableNewMyJoveSectionDesign

educationFeatures

seoMetaApi

ai_copilot_institution_blacklist

ai_chat_institution_blacklist

freeAccessWindow

ssoRoleCapture

scheduledMaintenanceBanner

joveLabsFeatures

disable_autoplay_for_bots

extended_trial_duration

5 minutes

P.A. acknowledges support from the U.S. National Science Foundation (NSF) CAREER under award No. DMR-1654482. Material synthesis was carried out with the support of the Polish National Science Centre grant No 2011/01/B/ST3/00425.

NOTE: The U-shaped body is made of 416-grade stainless steel, which is stiff and has a low coefficient of thermal expansion (CTE), ~9.9 &#956;m/(m&#8729;&#176;C), as compared to ~17.3 &#956;m/(m&#8729;&#176;C) for 304-grade stainless steel.
1. Mechanical uniaxial-strain device
<ol>
	<li>Clean the U-shaped device, the micrometer screws (1&#8211;72 corresponding to 72 rotations per inch), the Belleville spring disks, and the base plate by sonicating them separately in acetone first and then in isopropanol, for 20 min each, in an ultrasonic bath sonicator. This removes any impurities/particles. This process should be carried out in the hood.</li>
	<li>Bake them in an oven for 15&#8211;20 min to get rid of any water residue and to degas.</li>
	<li>Using a sharp razor blade, while observing under an optical microscope, cut the Fe1+YTe sample to size, namely 1 mm x 2 mm x 0.1 mm.</li>
	<li>Assemble the parts together as shown in Figure 1C, first panel. The opening inside the U is 1 mm and can be tuned smaller or large by a pair of micrometer screws located on the sides of the device.</li>
</ol>
2. Application of the strain
<ol>
	<li>In two separate dishes, mix silver epoxy (H20E) and nonconductive epoxy (H74F) according to the instructions on the epoxy data sheet.</li>
	<li>On the U-shaped device, apply a thin layer of silver epoxy (H20E) to create electrical contact, and mount the sample (of a size of 1 mm x 2 mm x ~0.1 mm) with its long axis oriented along the b-axis of the Fe1+yTe sample, on top of the device, across the 1 mm gap, as shown in Figure 1C. In a convection oven, bake the device for 15 min at 120 &#176;C.</li>
	<li>Cover the two sides of the sample with nonconductive epoxy so that the sample is firmly supported on the device. Bake for 20 min at 100 &#176;C.
	<ol>
		<li>Using an optical microscope, examine the position of the sample from all angles to check for a parallel alignment of the sides of the sample with the gap.</li>
		<li>Optionally, place samples within the gap and enforced by H20E and H74F epoxy (Figure 1C).</li>
	</ol>
	</li>
	<li>Under an optical microscope, apply compressive strain by rotating the micrometer screw while observing the surface of the sample. 
	NOTE: Here we applied a 50&#176; strain, but this can be modified depending on the amount of strain to be applied to the sample. The pressure is transferred to the sample by a series of Belleville spring disks. There should be no cracks or bending of the sample after the pressure is applied.</li>
	<li>Screw the device onto the base plate as shown in Figure 1B.
	<ol>
		<li>Apply a thin layer of silver epoxy (H20E) from the base plate onto the U-shaped device to create electrical contact between the sample and the plate. Bake for 15 min at 120 &#176;C. Measure the electrical contact using a multimeter.</li>
		<li>Using a thin layer of H74F nonconducting epoxy, glue an aluminum post (the same size as the sample) onto the strained sample, perpendicular to the a-b cleaving plane. Bake the assembled device for 20 min until the epoxy is cured.</li>
	</ol>
	</li>
</ol>
3. Transfer of the device to the scanning tunneling microscope head
<ol>
	<li>Transfer the staining device with the sample and the post through the loading dock of the variable-temperature, ultrahigh vacuum scanning tunneling microscope, to the analysis chamber (see Figure 2A).</li>
	<li>Using an arm manipulator, knock off the aluminum post in ultrahigh vacuum at room temperature, to expose a freshly cleaved surface.</li>
	<li>Immediately transfer the device (with the strained sample) in situ with another set of manipulators to the scanning tunneling microscope chamber and to the microscope head (see Figure 2B), which has been cooled down to 9 K. Carry out all experiments at 9 K.</li>
	<li>Allow the sample to cool down overnight before carrying out the next steps.</li>
</ol>
4. Carrying out the STM experiments
<ol>
	<li>Prepare the Pt-Ir tips prior to each experiment by field emission on a Cu (111) surface that has been treated with several rounds of sputtering and annealing.</li>
	<li>Using the voltage applied to the piezoelectric materials in the microscope by an external controller, move the sample stage to align with the tip, then follow by approaching the sample.</li>
	<li>Once the tip is a few &#197; away from the sample and the tunneling current is registered on the oscilloscope, take topographs at different setpoint biases and setpoint currents. 
	NOTE: The scanning tunneling microscope is controlled by manufacturer-provided controller and software. For the operation of the microscope, please refer to the user manual/tutorials (http://www.rhk-tech.com/support/tutorials/).</li>
</ol>

<ol><li>Paglione, J., Greene, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((High-temperature+superconductivity+in+iron-based+materials%5BTitle%5D)+AND+%22Nature+Physics%22%5BJournal%5D)">High-temperature superconductivity in iron-based materials.</a> Nature Physics. 6 (9), 645(2010).</li>
<li>Keimer, B., Kivelson, S. A., Norman, M. R., Uchida, S., Zaanen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((From+quantum+matter+to+high-temperature+superconductivity+in+copper+oxides%5BTitle%5D)+AND+%22Nature%22%5BJournal%5D)">From quantum matter to high-temperature superconductivity in copper oxides.</a> Nature. 518, 179-186 (2015).</li>
<li>Anderson, P. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Physics%3A+The+opening+to+complexity%5BTitle%5D)+AND+%22Proceedings+of+the+National+Academy+of+Sciences+of+the+United+States+of+America%22%5BJournal%5D)">Physics: The opening to complexity.</a> Proceedings of the National Academy of Sciences of the United States of America. 92 (15), 6653-6654 (1995).</li>
<li>Dagotto, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Complexity+in+strongly+correlated+electronic+systems%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">Complexity in strongly correlated electronic systems.</a> Science. 309, 257-262 (2005).</li>
<li>Davis, J. S., Lee, D. -H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Concepts+relating+magnetic+interactions%2C+intertwined+electronic+orders%2C+and+strongly+correlated+superconductivity%5BTitle%5D)+AND+%22Proceedings+of+the+National+Academy+of+Sciences+of+the+United+States+of+America%22%5BJournal%5D)">Concepts relating magnetic interactions, intertwined electronic orders, and strongly correlated superconductivity.</a> Proceedings of the National Academy of Sciences of the United States of America. 110 (44), 17623-17630 (2013).</li>
<li>Fernandes, R., Chubukov, A., Schmalian, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((What+drives+nematic+order+in+iron-based+superconductors%5BTitle%5D)+AND+%22Nature+Physics%22%5BJournal%5D)">What drives nematic order in iron-based superconductors.</a> Nature Physics. 10 (2), 97(2014).</li>
<li>Fradkin, E., Kivelson, S. A., Tranquada, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Colloquium%3A+Theory+of+intertwined+orders+in+high+temperature+superconductors%5BTitle%5D)+AND+%22Reviews+of+Modern+Physics%22%5BJournal%5D)">Colloquium: Theory of intertwined orders in high temperature superconductors.</a> Reviews of Modern Physics. 87 (2), 457(2015).</li>
<li>Stillwell, E., Skove, M., Davis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Two+%E2%80%9CWhisker%E2%80%9D+Straining+Devices+Suitable+for+Low+Temperatures%5BTitle%5D)+AND+%22Review+of+Scientific+Instruments%22%5BJournal%5D)">Two “Whisker” Straining Devices Suitable for Low Temperatures.</a> Review of Scientific Instruments. 39 (2), 155-157 (1968).</li>
<li>Shayegan, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Low-temperature%2C+in+situ+tunable%2C+uniaxial+stress+measurements+in+semiconductors+using+a+piezoelectric+actuator%5BTitle%5D)+AND+%22Applied+Physics+Letters%22%5BJournal%5D)">Low-temperature, in situ tunable, uniaxial stress measurements in semiconductors using a piezoelectric actuator.</a> Applied Physics Letters. 83 (25), 5235-5237 (2003).</li>
<li>Chu, J. -H., Kuo, H. -H., Analytis, J. G., Fisher, I. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Divergent+nematic+susceptibility+in+an+iron+arsenide+superconductor%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">Divergent nematic susceptibility in an iron arsenide superconductor.</a> Science. 337 (6095), 710-712 (2012).</li>
<li>Song, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Uniaxial+pressure+effect+on+structural+and+magnetic+phase+transitions+in+NaFeAs+and+its+comparison+with+as-grown+and+annealed+BaFe2As2%5BTitle%5D)+AND+%22Physical+Review+B%22%5BJournal%5D)">Uniaxial pressure effect on structural and magnetic phase transitions in NaFeAs and its comparison with as-grown and annealed BaFe2As2.</a> Physical Review B. 87 (18), 184511(2013).</li>
<li>Allan, M. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Anisotropic+impurity+states%2C+quasiparticle+scattering+and+nematic+transport+in+underdoped+Ca%28Fe1%E2%88%92xCox%292As2%5BTitle%5D)+AND+%22Nature+Physics%22%5BJournal%5D)">Anisotropic impurity states, quasiparticle scattering and nematic transport in underdoped Ca(Fe1−xCox)2As2.</a> Nature Physics. 9 (4), 220-224 (2013).</li>
<li>Hicks, C. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Strong+increase+of+Tc+of+Sr2RuO4+under+both+tensile+and+compressive+strain%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">Strong increase of Tc of Sr2RuO4 under both tensile and compressive strain.</a> Science. 344 (6181), 283-285 (2014).</li>
<li>Hicks, C. W., Barber, M. E., Edkins, S. D., Brodsky, D. O., Mackenzie, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Piezoelectric-based+apparatus+for+strain+tuning%5BTitle%5D)+AND+%22Review+of+Scientific+Instruments%22%5BJournal%5D)">Piezoelectric-based apparatus for strain tuning.</a> Review of Scientific Instruments. 85 (6), 065003(2014).</li>
<li>Gannon, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+device+for+the+application+of+uniaxial+strain+to+single+crystal+samples+for+use+in+synchrotron+radiation+experiments%5BTitle%5D)+AND+%22Review+of+Scientific+Instruments%22%5BJournal%5D)">A device for the application of uniaxial strain to single crystal samples for use in synchrotron radiation experiments.</a> Review of Scientific Instruments. 86 (10), 103904(2015).</li>
<li>Kretzschmar, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Critical+spin+fluctuations+and+the+origin+of+nematic+order+in+Ba%28Fe1%E2%88%92xCox%292As+2%5BTitle%5D)+AND+%22Nature+Physics%22%5BJournal%5D)">Critical spin fluctuations and the origin of nematic order in Ba(Fe1−xCox)2As 2.</a> Nature Physics. 12 (6), 560(2016).</li>
<li>Steppke, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Strong+peak+in+T+c+of+Sr2RuO4+under+uniaxial+pressure%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">Strong peak in T c of Sr2RuO4 under uniaxial pressure.</a> Science. 355 (6321), 133(2017).</li>
<li>Yim, C. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Discovery+of+a+strain-stabilised+smectic+electronic+order+in+LiFeAs%5BTitle%5D)+AND+%22Nature+Communications%22%5BJournal%5D)">Discovery of a strain-stabilised smectic electronic order in LiFeAs.</a> Nature Communications. 9 (1), 2602(2018).</li>
<li>Gao, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Atomic-scale+strain+manipulation+of+a+charge+density+wave%5BTitle%5D)+AND+%22Proceedings+of+the+National+Academy+of+Sciences+of+the+United+States+of+America%22%5BJournal%5D)">Atomic-scale strain manipulation of a charge density wave.</a> Proceedings of the National Academy of Sciences of the United States of America. 115 (27), 6986-6990 (2018).</li>
<li>Jiang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Distinct+in-plane+resistivity+anisotropy+in+a+detwinned+FeTe+single+crystal%3A+Evidence+for+a+Hund%27s+metal%5BTitle%5D)+AND+%22Physical+Review+B%22%5BJournal%5D)">Distinct in-plane resistivity anisotropy in a detwinned FeTe single crystal: Evidence for a Hund's metal.</a> Physical Review B. 88 (11), 115130(2013).</li>
<li>Zhang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Symmetry+breaking+via+orbital-dependent+reconstruction+of+electronic+structure+in+detwinned+NaFeAs%5BTitle%5D)+AND+%22Physical+Review+B%22%5BJournal%5D)">Symmetry breaking via orbital-dependent reconstruction of electronic structure in detwinned NaFeAs.</a> Physical Review B. 85 (8), 085121(2012).</li>
<li>Watson, M. D., Haghighirad, A. A., Rhodes, L. C., Hoesch, M., Kim, T. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Electronic+anisotropies+revealed+by+detwinned+angle-resolved+photo-emission+spectroscopy+measurements+of+FeSe%5BTitle%5D)+AND+%22New+Journal+of+Physics%22%5BJournal%5D)">Electronic anisotropies revealed by detwinned angle-resolved photo-emission spectroscopy measurements of FeSe.</a> New Journal of Physics. 19 (10), 103021(2017).</li>
<li>Iida, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Strong+T+c+dependence+for+strained+epitaxial+Ba%28Fe1-xCox%292As2+thin+films%5BTitle%5D)+AND+%22Applied+Physics+Letters%22%5BJournal%5D)">Strong T c dependence for strained epitaxial Ba(Fe1-xCox)2As2 thin films.</a> Applied Physics Letters. 95 (19), 192501(2009).</li>
<li>Stern, A., Dzero, M., Galitski, V., Fisk, Z., Xia, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Surface-dominated+conduction+up+to+240+K+in+the+Kondo+insulator+SmB+6+under+strain%5BTitle%5D)+AND+%22Nature+Materials%22%5BJournal%5D)">Surface-dominated conduction up to 240 K in the Kondo insulator SmB 6 under strain.</a> Nature Materials. 16 (7), 708-711 (2017).</li>
<li>Iida, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Hall-plot+of+the+phase+diagram+for+Ba%28Fe1%E2%88%92xCox%292As2%5BTitle%5D)+AND+%22Scientific+Reports%22%5BJournal%5D)">Hall-plot of the phase diagram for Ba(Fe1−xCox)2As2.</a> Scientific Reports. 6, 28390(2016).</li>
<li>Hänke, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Reorientation+of+the+diagonal+double-stripe+spin+structure+at+Fe1%2ByTe+bulk+and+thin-film+surfaces%5BTitle%5D)+AND+%22Nature+Communications%22%5BJournal%5D)">Reorientation of the diagonal double-stripe spin structure at Fe1+yTe bulk and thin-film surfaces.</a> Nature Communications. 8, 13939(2017).</li>
<li>Takeshita, N., Sasagawa, T., Sugioka, T., Tokura, Y., Takagi, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Gigantic+anisotropic+uniaxial+pressure+effect+on+superconductivity+within+the+CuO2+plane+of+La1.64Eu0.2Sr0.16CuO4%3A+Strain+control+of+stripe+criticality%5BTitle%5D)+AND+%22Journal+of+the+Physical+Society+of+Japan%22%5BJournal%5D)">Gigantic anisotropic uniaxial pressure effect on superconductivity within the CuO2 plane of La1.64Eu0.2Sr0.16CuO4: Strain control of stripe criticality.</a> Journal of the Physical Society of Japan. 73 (5), 1123-1126 (2004).</li>
<li>Kuo, H. -H., Shapiro, M. C., Riggs, S. C., Fisher, I. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Measurement+of+the+elastoresistivity+coefficients+of+the+underdoped+iron+arsenide+Ba%28Fe0.975Co0.025%292As2%5BTitle%5D)+AND+%22Physical+Review+B%22%5BJournal%5D)">Measurement of the elastoresistivity coefficients of the underdoped iron arsenide Ba(Fe0.975Co0.025)2As2.</a> Physical Review B. 88 (8), 085113(2013).</li>
<li>He, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Dichotomy+between+in-plane+magnetic+susceptibility+and+resistivity+anisotropies+in+extremely+strained+BaFe2As2%5BTitle%5D)+AND+%22Nature+Communications%22%5BJournal%5D)">Dichotomy between in-plane magnetic susceptibility and resistivity anisotropies in extremely strained BaFe2As2.</a> Nature Communications. 8 (1), 504(2017).</li>
<li>Engelmann, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Strain+induced+superconductivity+in+the+parent+compound+BaFe2As2%5BTitle%5D)+AND+%22Nature+Communications%22%5BJournal%5D)">Strain induced superconductivity in the parent compound BaFe2As2.</a> Nature Communications. 4 (2877), 2877(2013).</li>
<li>Berger, A. D. N., et al. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=%22Temperature+Driven+Topological+Switch+in+1T%E2%80%99-MoTe2+and+Strain+Induced+Nematicity+in+NaFeAs%22">Temperature Driven Topological Switch in 1T’-MoTe2 and Strain Induced Nematicity in NaFeAs</a>. , Columbia University. Doctoral dissertation (2018).</li>
<li>Böhmer, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effect+of+biaxial+strain+on+the+phase+transitions+of+Ca%28Fe1%E2%88%92xCox%292As2%5BTitle%5D)+AND+%22Physical+Review+Letters%22%5BJournal%5D)">Effect of biaxial strain on the phase transitions of Ca(Fe1−xCox)2As2.</a> Physical Review Letters. 118 (10), 107002(2017).</li>
<li>Bao, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Tunable+%28%CE%B4+%CF%80%2C+%CE%B4+%CF%80%29-type+antiferromagnetic+order+in+%CE%B1-Fe%28Te%2CSe%29+superconductors%5BTitle%5D)+AND+%22Physical+Review+Letters%22%5BJournal%5D)">Tunable (δ π, δ π)-type antiferromagnetic order in α-Fe(Te,Se) superconductors.</a> Physical Review Letters. 102 (24), 247001(2009).</li>
<li>Koz, C., Rößler, S., Tsirlin, A. A., Wirth, S., Schwarz, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Low-temperature+phase+diagram+of+Fe1%2ByTe+studied+using+x-ray+diffraction%5BTitle%5D)+AND+%22Physical+Review+B%22%5BJournal%5D)">Low-temperature phase diagram of Fe1+yTe studied using x-ray diffraction.</a> Physical Review B. 88 (9), 094509(2013).</li>
<li>Enayat, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Real-space+imaging+of+the+atomic-scale+magnetic+structure+of+Fe1%2ByTe%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">Real-space imaging of the atomic-scale magnetic structure of Fe1+yTe.</a> Science. 345 (6197), 653-656 (2014).</li>
<li>Singh, U. R., Aluru, R., Liu, Y., Lin, C., Wahl, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Preparation+of+magnetic+tips+for+spin-polarized+scanning+tunneling+microscopy+on+Fe1%2ByTe%5BTitle%5D)+AND+%22Physical+Review+B%22%5BJournal%5D)">Preparation of magnetic tips for spin-polarized scanning tunneling microscopy on Fe1+yTe.</a> Physical Review B. 91 (16), 161111(2015).</li>
<li>Chandra, S., Islam, A. K. M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Elastic+and+electronic+properties+of+PbO-type+FeSe1-xTex+%28x%3D+0-1.0%29%3A+A+first-principles+study%5BTitle%5D)+AND+%22ArXiv+preprint%22%5BJournal%5D)">Elastic and electronic properties of PbO-type FeSe1-xTex (x= 0-1.0): A first-principles study.</a> ArXiv preprint. , arXiv:1008.1448 (2010).</li>
</ol>

The authors have nothing to disclose.

All operations required to move the samples into and inside the STM are carried out using sets of arm manipulators. The STM is maintained at low temperatures by liquid nitrogen and liquid helium, and the sample cools down for at least 12 h before being approached. This allows the sample and microscope temperature to reach thermal equilibrium. To isolate electric and acoustic noise, the STM is placed in an acoustic and radio frequency shielded room. The microscope head is further suspended from springs for optimized instr...

High-temperature superconductivity in cuprates and iron-based superconductors is an intriguing state of quantum matter1,2. A major challenge in understanding superconductivity is the locally intertwined nature of various broken symmetry states, such as electronic nematic and smectic phases (that break rotational and translational symmetries of the electronic states), with superconductivity3,4,5,6,7. Manipulation and deliberate tuning of these broken symmetry states is a key objective toward understanding and controlling superconductivity.
Controlled strain, both uniaxial and biaxial, is a well-established technique to tune the collective electronic states in condensed matter systems8,9,10,11,12,13,14,15,16,17,18,19,20,21,22. This clean tuning, without the introduction of disorder through chemical doping, is commonly used in various kinds of experiments to tune bulk electronic properties23,24,25,26. For example, uniaxial pressure has proved to have an immense effect on superconductivity in Sr2RuO413 and cuprates27 and on the structural, magnetic, and nematic phase transitions of iron-based superconductors10,14,28,29 and was recently demonstrated in tuning the topological states of SmB624. However, the use of strain in surface-sensitive techniques, such as STM and angle-resolved photoemission spectroscopy (ARPES), has been limited to in situ-grown thin films on mismatched substrates26,30. The major challenge with applying strain to single crystals in surface-sensitive experiments is the need to cleave the strained samples in ultrahigh vacuum (UHV). In the last few years, an alternative direction has been to epoxy a thin sample on piezo stacks9,10,18,31 or on plates with different coefficients of thermal expansion19,32. Yet in both cases, the magnitude of the applied strain is quite limited.
Here we demonstrate the use of a novel mechanical uniaxial-strain device that allows researchers to strain a sample (compressive strain) without constraints and simultaneously visualize its surface structure using STM (see Figure 1). As an example, we use single crystals of Fe1+yTe, where y = 0.10, the parent compound of the iron chalcogenide superconductors (y is the excess iron concentration). Below TN = ~60 K, Fe1+yTe transitions from a high-temperature paramagnetic state into a low-temperature antiferromagnetic state with a bicollinear stripe magnetic order26,33,34&#160;(see Figure 3A,B). The magnetic transition is further accompanied by a structural transition from tetragonal to monoclinic26,35. The in-plane AFM order forms detwinned domains with the spin structure pointing along the long b-direction of the orthorhombic structure34. By visualizing the AFM order with spin-polarized STM, we probe the bidirectional domain structure in unstrained Fe1+yTe samples and observe their transition into a single large domain under applied strain (see the schematic in Figure 3C-E). These experiments show the successful surface tuning of the single crystals using the uniaxial-strain device presented here, the cleaving of the sample, and the simultaneous imaging of its surface structure with the scanning tunneling microscope. Figure 1 shows the schematic drawings and pictures of the mechanical strain device.

<table><tbody><tr><td>Belleville spring disks</td><td>McMaster Carr</td><td></td><td></td></tr><tr><td>Fe(1.1)Te</td><td></td><td></td><td>Single Crystal</td></tr><tr><td>H20E</td><td>Epoxy Technology</td><td></td><td></td></tr><tr><td>H74F</td><td>Epoxy Technology</td><td></td><td></td></tr><tr><td>Micrometer screws</td><td>McMaster Carr</td><td></td><td></td></tr><tr><td>Stainless Steel sheets (416)</td><td>McMaster Carr</td><td></td><td></td></tr></tbody></table>

visualizing uniaxial-strain manipulation of antiferromagnetic domains in fe1+yte using a spin-polarized scanning tunneling microscope

Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope

The quest to understand correlated electronic systems has pushed the frontiers of experimental measurements toward the development of new experimental techniques and methodologies. Here we use a novel home-built uniaxial-strain device integrated into our variable temperature scanning tunneling microscope that enables us to controllably manipulate in-plane uniaxial strain in samples and probe their electronic response at the atomic scale. Using scanning tunneling microscopy (STM) with spin-polarization techniques, we visualize antiferromagnetic (AFM) domains and their atomic structure in Fe1+yTe samples, the parent compound of iron-based superconductors, and demonstrate how these domains respond to applied uniaxial strain. We observe the bidirectional AFM domains in the unstrained sample, with an average domain size of ~50-150 nm, to transition into a single unidirectional domain under applied uniaxial strain. The findings presented here open a new direction to utilize a valuable tuning parameter in STM, as well as other spectroscopic techniques, both for tuning the electronic properties as for inducing symmetry breaking in quantum material systems.

STM topographs were measured in constant current mode with a setpoint bias of -12 meV applied to the sample and a setpoint current of -1.5 nA collected on the tip. Pt-Ir tips were used in all experiments. To achieve spin-polarized STM, the scanning tunneling microscope tip has to be coated with magnetic atoms, which can be quite challenging. In this case of studying Fe1+yTe, the sample itself provides a simple means of achieving this. The excess irons (y...

Using uniaxial strain combined with spin-polarized scanning tunneling microscopy, we visualize and manipulate the antiferromagnetic domain structure of Fe1+yTe, the parent compound of iron-based superconductors.

The quest to understand correlated electronic systems has pushed the frontiers of experimental measurements toward the development of new experimental ...

visualizing-uniaxial-strain-manipulation-antiferromagnetic-domains

Research

JoVE Journal

Engineering

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

A method to prepare epitaxial layers of ordered alloys by sputtering is described. The B2-ordered FeRh compound is used as an example, as it displays a metamagnetic transition that depends sensitively on the degree of chemical order and the exact composition of the alloy.

Sputter Growth and Characterization of Metamagnetic B2-ordered FeRh Epilayers

We present a protocol for manipulation of individual vortices in thin superconducting films, using local mechanical contact. The method does not include applying current, magnetic field or additional fabrication steps.

Scanning SQUID Study of Vortex Manipulation by Local Contact

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

This paper elaborates the sample and sensor preparation procedures and the protocols for using the test rig particularly for dynamic domain imaging with in situ BH measurements in order to achieve optimal domain pattern quality and accurate BH measurements.

Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement

Here, we combine polarization-variable 7-eV laser with spin- and angle-resolved photoemission technique to visualize the spin-orbital coupling effect in solid states.

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser

In this report, we present a protocol to examine direct magnetoelectric effects, i.e., induction of ferroelectric polarization by applying magnetic fields, in liquid crystals. This protocol provides a unique approach, supported by the softness of liquid crystals, to achieve room-temperature magnetoelectrics.

Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals

Photonic band structure enables understanding how confined electromagnetic modes propagate within a photonic crystal. In photonic crystals that incorporate magnetic elements, such confined and resonant optical modes are accompanied by enhanced and modified magneto-optical activity. We describe a measurement procedure to extract the magneto-optical band structure by Fourier space microscopy.

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures

This work presents a workflow for atomic position tracking in atomic resolution transmission electron microscopy imaging. This workflow is performed using an open-source Matlab app (EASY-STEM).

Picometer-Precision Atomic Position Tracking through Electron Microscopy

Magnetic force microscopy (MFM) employs a vertically magnetized atomic force microscopy probe to measure sample topography and local magnetic field strength with nanoscale resolution. Optimizing MFM spatial resolution and sensitivity requires balancing decreasing lift height against increasing drive (oscillation) amplitude, and benefits from operating in an inert atmosphere glovebox.

Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains

Learn to visualize antiferromagnetic domains in Fe1+yTe using uniaxial strain and spin-polarized scanning tunneling microscopy. This technique enables precise manipulation of structural domains in superconductors.

Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope (Video) | JoVE Journal

Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe₁₊_YTe Using a Spin-polarized Scanning Tunneling Microscope

Explore More Videos