Possible transport evidence for three-dimensional topological superconductivity in doped β-PdBi2
Abstract
Interest in topological states of matter burgeoned over a decade ago with the theoretical prediction and experimental detection of topological insulators, especially in bulk three-dimensional insulators that can be tuned out of it by doping. Their superconducting counterpart, the fully-gapped three-dimensional time-reversal-invariant topological superconductors, have evaded discovery in bulk intrinsic superconductors so far. The recently discovered topological metal β-PdBi2 is a unique candidate for tunable bulk topological superconductivity because of its intrinsic superconductivity and spin-orbit-coupling. In this work, we provide experimental transport signatures consistent with fully-gapped 3D time-reversal-invariant topological superconductivity in K-doped β-PdBi2. In particular, we find signatures of odd-parity bulk superconductivity via upper-critical field and magnetization measurements— odd-parity pairing can be argued, given the band structure of β-PdBi2, to result in 3D topological superconductivity. In addition, Andreev spectroscopy reveals surface states protected by time-reversal symmetry which might be possible evidence of Majorana surface states (Majorana cone). Moreover, we find that the undoped bulk system is a trivial superconductor. Thus, we discover β-PdBi2 as a unique bulk material that, on doping, can potentially undergo an unprecedented topological quantum phase transition in the superconducting state.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 29, 2019
- Source ID
- 10.1038/s41598-019-48906-7
Entities
People
- Ayo Kolapo
- John H. Miller Jr.
- Pavan Hosur
- Tingxin Li
Organizations
- Air Force Office of Scientific Research
- National Science Foundation