Quantum-metric Bloch oscillations in weakly inhomogeneous electric fields

TL;DR

This paper reveals that weakly inhomogeneous electric fields induce quantum-metric-driven Bloch oscillations, leading to novel real-space oscillatory transport effects even without Berry curvature.

Contribution

It introduces a new quantum-metric term in semiclassical dynamics caused by inhomogeneous fields, expanding understanding beyond Berry curvature effects.

Findings

Inhomogeneous fields generate oscillations via quantum metric.

Transport response includes intrinsic and scattering-time-dependent parts.

Scattering-time-dependent response can dominate and saturate at high fields.

Abstract

Geometric analogs of Bloch oscillations studied so far have relied on Berry curvature. We show that a weakly inhomogeneous electric field adds a distinct quantum-metric term to semiclassical wavepacket dynamics, generating an oscillatory real-space contribution even when the Berry curvature vanishes. The associated transport response comprises an intrinsic and a scattering-time-dependent part. In the regime studied, the latter can dominate and approach finite saturation at high field when the relative field inhomogeneity is held fixed. A tilted Dirac model illustrates the mechanism. Realistic platforms will likely require synthetically engineered superlattices, with a finite quantum metric and an adequate band gap.