A unique van Hove singularity in kagome superconductor CsV3-xTaxSb5 with enhanced superconductivity.
Nat Commun
; 14(1): 3819, 2023 Jun 28.
Article
em En
| MEDLINE
| ID: mdl-37369675
Van Hove singularity (VHS) has been considered as a driving source for unconventional superconductivity. A VHS in two-dimensional (2D) materials consists of a saddle point connecting electron-like and hole-like bands. In a rare case, when a VHS appears at Fermi level, both electron-like and hole-like conduction can coexist, giving rise to an enhanced density of states as well as an attractive component of Coulomb interaction for unconventional electronic pairing. However, this van Hove scenario is often destroyed by an incorrect chemical potential or competing instabilities. Here, by using angle-resolved photoemission measurements, we report the observation of a VHS perfectly aligned with the Fermi level in a kagome superconductor CsV3-xTaxSb5 (x ~ 0.4), in which a record-high superconducting transition temperature is achieved among all the current variants of AV3Sb5 (A = Cs, Rb, K) at ambient pressure. Doping dependent measurements reveal the important role of van Hove scenario in boosting superconductivity, and spectroscopic-imaging scanning tunneling microscopy measurements indicate a distinct superconducting state in this system.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article