Artificial gravity field, astrophysical analogues, and topological phase transitions in strained topological semimetals

TL;DR

This paper explores how strain in topological semimetals can simulate astrophysical phenomena like black holes and gravitational lensing, induce topological phase transitions, and enable novel device applications such as piezo-topological transistors.

Contribution

It demonstrates that lattice strain in topological semimetals can create spacetime analogues, induce topological phase transitions, and proposes a new device concept based on these effects.

Findings

Strain can simulate black-hole and white-hole horizons.

Strain induces topological phase transitions in bulk and thin films.

Proposes a piezo-topological transistor device.

Abstract

Effective gravity and gauge fields are emergent properties intrinsic for low-energy quasiparticles in topological semimetals. Here, taking two Dirac semimetals as examples, we demonstrate that applied lattice strain can generate warped spacetime, with fascinating analogues in astrophysics. Particularly, we study the possibility of simulating black-hole/white-hole event horizons and gravitational lensing effect. Furthermore, we discover strain-induced topological phase transitions, both in the bulk materials and in their thin films. Especially in thin films, the transition between the quantum spin Hall and the trivial insulating phases can be achieved by a small strain, naturally leading to the proposition of a novel piezo-topological transistor device. Possible experimental realizations and analogue of Hawking radiation effect are discussed. Our result bridges multiple disciplines, revealing topological semimetals as a unique table-top platform for exploring interesting phenomena in astrophysics and general relativity; it also suggests realistic materials and methods to achieve controlled topological phase transitions with great potential for device applications.