Escape from black holes in materials: Type II Weyl semimetals and generic edge states

TL;DR

This paper explores how certain boundary conditions in Type II Weyl semimetals allow edge states to escape from black hole-like regions, highlighting the importance of boundary choices in these materials.

Contribution

It derives generic boundary conditions for Type II Weyl semimetals and demonstrates that edge states can escape the black hole analogy under specific boundary conditions.

Findings

Edge states can escape the black hole horizon with certain boundary conditions.

Boundary conditions are crucial for the behavior of surface states in Type II Weyl semimetals.

Careful boundary engineering is necessary to realize black hole analogies in these materials.

Abstract

Type II Weyl semimetals are dictated by bulk excitations with tilted light cones, resembling the inside of black holes. We obtain generic boundary conditions for surface boundaries of the type II Weyl semimetals near Weyl nodes, and show that for a certain boundary condition edge states can escape out of the "black hole" event horizon. This means that for realization of the material "black hole" by the Type II Weyl semimetals a careful choice of the boundary condition is necessary.