Uniform Diffusion of Cooper Pairing Mediated by Hole Carriers in Topological Sb2Te3/Nb

• Published in: ACS nano 2024-11, Vol.18 (45), p.31323-31331
• Main Authors: Hlevyack, Joseph A., Najafzadeh, Sahand, Li, Yao, Nagashima, Tsubaki, Mine, Akifumi, Zhong, Yigui, Suzuki, Takeshi, Fukushima, Akiko, Lin, Meng-Kai, Suresh Babu, Soorya, Hwang, Jinwoong, Lee, Ji-Eun, Mo, Sung-Kwan, Eckstein, James N., Shin, Shik, Okazaki, Kozo, Chiang, Tai-Chang
• Format: Article
• Language: English
• Subjects: energy; flip-chip method; interband superconducting coherence; p-doped topological insulators; photoemission; Proximity effects; thickness; thin films; thin-film heterostructures; topological insulator; topological superconductivity
• ISSN: 1936-0851; 1936-086X; 1936-086X
• DOI: 10.1021/acsnano.4c10533

Spin-helical Dirac Fermions at a doped topological insulator’s boundaries can support Majorana quasiparticles when coupled with s-wave superconductors, but in n-doped systems, the requisite induced Cooper pairing in topological states is often buried at heterointerfaces or complicated by degenerate coupling with bulk conduction carriers. Rarely probed are p-doped topological structures with nondegenerate Dirac and bulk valence bands at the Fermi level, which may foster long-range superconductivity without sacrificing Majorana physics. Using ultrahigh-resolution photoemission, we report proximity pairing with a large decay length in p-doped topological Sb2Te3 on superconducting Nb. Despite no momentum-space degeneracy, the topological and bulk states of Sb2Te3/Nb exhibit the same isotropic superconducting gaps at low temperatures. Our results unify principles for realizing accessible pairing in Dirac Fermions relevant to topological superconductivity.