Berry curvature generation detected by Nernst responses in ferroelectric Weyl semimetal

TL;DR

This study demonstrates a ferroelectric Weyl semimetal where Berry curvature is detected through Nernst responses, showing tunability of Weyl nodes and Berry curvature via ferroelectric order control in an indium-doped PbSnTe alloy.

Contribution

It introduces a ferroelectric nonmagnetic Weyl semimetal with tunable symmetry breaking and Berry curvature, using Nernst effect measurements as a probe.

Findings

Berry curvature generation detected via Nernst responses.

Weyl nodes and Berry curvature are tunable by ferroelectric order.

The material provides a platform for manipulating Weyl fermions in nonmagnetic systems.

Abstract

The quest for nonmagnetic Weyl semimetals with high tunability of phase has remained a demanding challenge. As the symmetry breaking control parameter, the ferroelectric order can be steered to turn on/off the Weyl semimetals phase, adjust the band structures around the Fermi level, and enlarge/shrink the momentum separation of Weyl nodes which generate the Berry curvature as the emergent magnetic field. Here, we report the realization of a ferroelectric nonmagnetic Weyl semimetal based on indium doped Pb1 xSnxTe alloy where the underlying inversion symmetry as well as mirror symmetry is broken with the strength of ferroelectricity adjustable via tuning indium doping level and Sn/Pb ratio. The transverse thermoelectric effect, i.e., Nernst effect both for out of plane and in plane magnetic field geometry, is exploited as a Berry curvature sensitive experimental probe to manifest the generation of Berry curvature via the redistribution of Weyl nodes under magnetic fields. The results demonstrate a clean non-magnetic Weyl semimetal coupled with highly tunable ferroelectric order, providing an ideal platform for manipulating the Weyl fermions in nonmagnetic system.