Quantum oscillations from networked topological interfaces in a Weyl semimetal

TL;DR

This paper reports the observation of quantum oscillations originating from topological interface states in a Weyl semimetal, specifically in a pressure-tuned mixed-phase of MoTe2, revealing new topological phenomena.

Contribution

It demonstrates that a mixed topological phase in MoTe2 exhibits coherent quantum oscillations due to topological interface states, a novel finding in topological materials.

Findings

Quantum oscillations observed in a structurally inhomogeneous phase.

Oscillations linked to topological interface states.

Potential for stabilizing multiple topological superconducting phases.

Abstract

Layered transition metal chalcogenides are promising hosts of electronic Weyl nodes and topological superconductivity. MoTe$_2$ is a striking example that harbors both noncentrosymmetric T$_d$ and centrosymmetric T' phases, both of which have been identified as topologically nontrivial. Applied pressure tunes the structural transition separating these phases to zero temperature, stabilizing a mixed T$_d$-T' matrix that entails a unique network of interfaces between the two non-trivial topological phases. Here, we show that this critical pressure range is characterized by unique coherent quantum oscillations, indicating that the change in topology between two phases give rise to a new topological interface state. A rare combination of topologically nontrivial electronic structures and locked-in transformation barriers leads to this counterintuitive situation wherein quantum oscillations can be observed in a structurally inhomogeneous material. These results open the possibility of stabilizing multiple topological superconducting phases, which are important for solving the decoherence problem in quantum computers.