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

Joseph A. Hlevyack, Sahand Najafzadeh, Yao Li, Tsubaki Nagashima, Akifumi Mine, Yigui Zhong, Takeshi Suzuki, Akiko Fukushima, Meng Kai Lin, Soorya Suresh Babu, Jinwoong Hwang, Ji Eun Lee, Sung Kwan Mo, James N. Eckstein, Shik Shin, Kozo Okazaki, Tai Chang Chiang

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish
Pages (from-to)31323-31331
Number of pages9
JournalACS Nano
Volume18
Issue number45
DOIs
StatePublished - 12 Nov 2024

Keywords

  • Proximity effects
  • flip-chip method
  • interband superconducting coherence
  • p-doped topological insulators
  • thin-film heterostructures
  • topological superconductivity

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