Ultrathin two-dimensional superconductivity with strong spin–orbit coupling
We report on a study of epitaxially grown ultrathin Pb films that are only a few atoms thick and have parallel critical magnetic fields much higher than the expected limit set by the interaction of electron spins with a magnetic field, that is, the Clogston–Chandrasekhar limit. The epitaxial thin fi...
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Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 113; no. 38; pp. 10513 - 10517 |
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Main Authors | , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
National Academy of Sciences
20.09.2016
Proceedings of the National Academy of Sciences |
Subjects | |
Online Access | Get full text |
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Summary: | We report on a study of epitaxially grown ultrathin Pb films that are only a few atoms thick and have parallel critical magnetic fields much higher than the expected limit set by the interaction of electron spins with a magnetic field, that is, the Clogston–Chandrasekhar limit. The epitaxial thin films are classified as dirty-limit superconductors because their mean-free paths, which are limited by surface scattering, are smaller than their superconducting coherence lengths. The uniformity of superconductivity in these thin films is established by comparing scanning tunneling spectroscopy, scanning superconducting quantum interference device (SQUID) magnetometry, double-coil mutual inductance, and magneto-transport, data that provide average superfluid rigidity on length scales covering the range from microscopic to macroscopic. We argue that the survival of superconductivity at Zeeman energies much larger than the superconducting gap can be understood only as the consequence of strong spin–orbit coupling that, together with substrate-induced inversionsymmetry breaking, produces spin splitting in the normal-state energy bands that is much larger than the superconductor’s energy gap. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 USDOE FG02-08ER46533; FG02- 07ER46420 2Present address: Department of Physics, University of Maryland, College Park, MD 20742. Contributed by Allan H. MacDonald, July 29, 2016 (sent for review March 21, 2016; reviewed by Eva Y. Andrei and Laura Greene) Author contributions: H.N., H.C., T.R.L., J.R.K., K.M., P.W.A., A.H.M., and C.-K.S. designed research; H.N., H.C., T.L., J.K., C.Z., J.Y., T.R.L., P.A.K., J.R.K., K.M., P.W.A., A.H.M., and C.-K.S. performed research; H.N., H.C., T.L., J.K., C.Z., J.Y., T.R.L., P.A.K., J.R.K., K.M., P.W.A., A.H.M., and C.-K.S. analyzed data; and H.N., H.C., T.R.L., J.R.K., K.M., P.W.A., A.H.M., and C.-K.S. wrote the paper. Reviewers: E.Y.A., Rutgers; and L.G., National Magnet Lab. 1Present address: Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803. |
ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.1611967113 |