Engineering superconductivity on the surface of Weyl semimetals

TL;DR

This paper explores how topological protection of surface states in Weyl semimetals can be used to engineer high-temperature surface superconductivity, focusing on the role of van Hove singularities and material modifications.

Contribution

It demonstrates that inducing van Hove singularities via surface modifications can significantly enhance superconducting critical temperatures in Weyl semimetals.

Findings

Surface van Hove singularities can be engineered by adding layers.

Critical temperature increases when the chemical potential is near singularities.

Topological protection enables manipulation of surface electronic states.

Abstract

Ten years after the experimental discovery of Weyl semimetals, theoretical and experimental work has pointed to the possibility of realizing surface-only superconductivity at relatively high temperatures in these materials. A consensus is developing that this unusual form of superconductivity is mediated by surface electronic states unique to Weyl semimetals, known as Fermi arcs. In this work, we show that the topological protection of these exotic states can be exploited to engineer high critical temperatures. Motivated by a real-material example (PtBi$_2$), we demonstrate that surface van Hove singularities can be induced by depositing a suitable additional layer on top of the Weyl surface. We also investigate the role of these singularities in raising the critical temperature, showing that it is significantly enhanced when the chemical potential lies in their vicinity. More generally, our results demonstrate how topological protection can be exploited to manipulate surface electronic states, thereby opening experimentally accessible routes toward engineering high-temperature two-dimensional superconductivity and other exotic phases.