Prediction of superconductivity and topological aspects in single-layer $\beta$-Bi$_{2}$Pd

TL;DR

This study uses first-principles calculations to explore the superconducting and topological properties of single-layer $eta$-Bi$_{2}$Pd, revealing potential for topological superconductivity and Majorana states in this material.

Contribution

It provides the first detailed theoretical prediction of superconductivity and topological states in monolayer $eta$-Bi$_{2}$Pd based on electronic and phononic analysis.

Findings

Single-layer $eta$-Bi$_{2}$Pd exhibits electron-phonon superconductivity.

The material has a continuous superconducting gap and topological Dirac-like boundary states.

Potential for one-dimensional topological superconductivity and Majorana bound states.

Abstract

Topological superconductors, characterized by topologically nontrivial states residing in a superconducting gap, are a recently discovered class of materials having Majorana Fermions. The interplay of superconductivity and topological states give rise to opportunities for achieving such topological superconductors in condensed matter systems. Up to now, several single-material topological superconductors in this form have been theoretically predicted and experimentally confirmed. Here, using the first-principles calculations, we study the superconducting single-layer $\beta$-Bi$_{2}$Pd. The electronic density of states near Fermi level of this monolayer are dominated by the Bi-p and Pd-d orbitals, forming a two-band Fermi surface with multi-class sheets. The presence of soft phonon bands, in cooperation with the electron susceptibility, account for electron-phonon superconductivity of single-layer $\beta$-Bi$_{2}$Pd. With the centrosymmetric structure, single-layer $\beta$-Bi$_{2}$Pd possesses a continuous gap over the whole Brillouin zone and topological Dirac-like states at its one-dimensional boundary. The present findings would lead to the expectation of one-dimensional topological superconductivity and Majorana bound states in monolayer candidate of $\beta$-Bi$_{2}$Pd with intrinsic full-gap superconductivity.