Topological phase transition in Dirac fermionic heterostructures

TL;DR

This paper explores topological phase transitions in heterostructures of Dirac fermions, revealing emergent phases and helicity ordering that influence the topological insulating properties, with implications for future technological applications.

Contribution

It introduces a new understanding of topological phases in layered heterostructures through first-principles calculations and a model, highlighting helicity ordering effects.

Findings

Helicity ordering occurs in real ternary chalcogen materials.

Emergent topological phases are driven by surface Dirac fermion interactions.

Potential for topological phases in device applications.

Abstract

Materials with non-trivial topology in their electronic structures enforce the existence of helical Dirac fermionic surface states. We discovered emergent topological phases in the stacked structures of topological insulator and band insulator layers where the surface Dirac fermions interact to each other with particular helicity ordering. Using first-principles calculations and a model Lagrangian, we explicitly demonstrated that such helicity ordering occurs in real materials of ternary chalcogen compounds and determines their topological insulating phase. Our results reveal the rich collective nature of interacting surface Dirac fermions, and pave the way for utilizing topological phases for technological devices such as non-volatile memories.