Monoclinic LaSb₂ Superconducting Thin Films
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1.
California Institute of Technology
Abstract
Rare-earth diantimondes exhibit coupling between structural and electronic orders, which are tunable under pressure and temperature. Here we present the discovery of a new polymorph of LaSb2 stabilized in thin films synthesized using molecular beam epitaxy. Using diffraction, electron microscopy, and first-principles calculations we identify a YbSb2-type monoclinic lattice as a yet-uncharacterized stacking configuration. The material hosts superconductivity with a Tc = 2 K, which is enhanced relative to the bulk ambient phase, and a long superconducting coherence length of 1730 Å. This result highlights the potential thin film growth has in stabilizing novel stacking configurations in quasi-two-dimensional compounds with competing layered structures.
Copyright and License
Acknowledgement
We thank Paul Canfield and Sergey Budko for helpful conversations and critical reading of the manuscript. J.F. acknowledges funding provided by the Air Force Office of Scientific Research (Grant number FA9550-22-1-0463), the Gordon and Betty Moore Foundation’s EPiQS Initiative (Grant number GBMF10638), and the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center (NSF Grant PHY-1733907). The work at CSUN acknowledges support from the NSF-PREP CSUN/Caltech-IQIM Partnership (Grant number 2216774) and NSF-PREM (Grant number DMR-1828019). We acknowledge the Beckman Institute for their support of the X-ray Crystallography Facility at Caltech. Electron microscopy was performed at the Center for Electron Microscopy and Analysis (CEMAS) at The Ohio State University.
Data Availability
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Additional text including experimental sections on molecular beam epitaxy, X-ray diffraction, transmission electron microscopy, first-principles calculations, transport measurements, and mutual inductance measurements; additional figures of RHEED data for growth, rocking curve and ϕ-scan of films, additional reciprocal space maps of films, calculated cleavage energy of films, comparison of stacking for SmSb2 and YbSb2, wide range resistance scans of films, temperature-dependent magnetotransport, calculated Fermi surfaces, wide-area TEM image, elemental mapping of films, line profiles of TEM data, temperature dependence of the superconducting transition (PDF)
Conflict of Interest
The authors declare no competing financial interest.
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Additional details
- ISSN
- 1530-6992
- FA9550-22-1-0463
- United States Air Force Office of Scientific Research
- GBMF10638
- Gordon and Betty Moore Foundation
- DMR-1828019
- National Science Foundation
- PHY-2216774
- National Science Foundation
- PHY-1733907
- National Science Foundation
- Caltech groups
- Institute for Quantum Information and Matter