Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session B44: New Venues for Unconventional and Topological 2D SuperconductivityInvited Live Streamed
|
Hide Abstracts |
Sponsoring Units: DCMP DMP Chair: Liang Fu, Massachusetts Institute of Technology MI Room: McCormick Place W-375C |
Monday, March 14, 2022 11:30AM - 12:06PM |
B44.00001: Signatures of unconventional 2D superconductivity in a bulk van der Waals superlattice Invited Speaker: Aravind Devarakonda Two-dimensional systems are expected to support a variety of exotic superconducting states, however, these states can be acutely sensitive to disorder. While two-dimensional (2D) superconductors are readily available by thin-film growth techniques or mechanical exfoliation, it remains a challenge to design and realize clean 2D superconductors, presenting an impediment to realizing these unusual states. Here we report on a bulk van der Waals superlattice Ba6Nb11S28 consisting of the transition metal dichalcogenide (TMD) superconductor H-NbS2 and a commensurate spacer layer Ba3NbS5 that yields enhanced two-dimensionality, high electronic quality, and clean-limit 2D superconductivity. With application of magnetic field parallel to the superconducting layers we observe long-anticipated signatures of 2D finite-momentum superconductivity. In parallel, analysis of quantum oscillations in the metallic state reveals topological bands with π Berry phase originating from commensuration between the TMD and spacer layer, suggesting a potential coexistence of topological and finite-momentum superconductivity. Finally, we comment on prospects of translating this superlattice construction to TMDs beyond H-NbS2 towards the realization of other unconventional 2D electronic states. |
Monday, March 14, 2022 12:06PM - 12:42PM |
B44.00002: Discovery of a Cooper-Pair Density Wave State in a Transition-Metal Dichalcogenide Invited Speaker: JC S Davis
|
Monday, March 14, 2022 12:42PM - 1:18PM |
B44.00003: Discovery of segmented Fermi surface induced by Cooper pair momentum Invited Speaker: Hao Zheng A sufficiently large supercurrent can close the energy gap in a superconductor and create gapless quasiparticles through the Doppler shift of quasiparticle energy caused by finite Cooper pair momentum. In this gapless superconducting state, zero-energy quasiparticles reside on a segment of the normal-state Fermi surface, whereas the remaining Fermi surface is still gapped. We use quasiparticle interference to image the field-controlled Fermi surface of Bi2Te3 thin films proximitized by the superconductor NbSe2. A small applied in-plane magnetic field induces a screening supercurrent, which leads to finite-momentum pairing on the topological surface states of Bi2Te3. We identify distinct interference patterns that indicate a gapless superconducting state with a segmented Fermi surface. Our results reveal the strong impact of finite Cooper pair momentum on the quasiparticle spectrum. |
Monday, March 14, 2022 1:18PM - 1:54PM |
B44.00004: New mechanism for unconventional superconductivity from repulsive interaction Invited Speaker: Valentin Crepel Within five years, the record of the most dilute superconductor has been broken several times, and an increasing number of materials, such as WTe2, SrTiO3, or graphitic heterostructures, host superconductivity at extremely low carrier densities. In this regime, however, the standard phonon-mechanism for superconductivity fails as the Fermi energy can be comparable to, or even smaller than, the Debye energy. To theoretically understand the above materials, we need new routes toward superconductivity, which stem from the repulsive Coulomb interaction itself and do not rely on Fermi surface renormalizations. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700