Interplay between disorder and inversion symmetry: Extreme enhancement of the mobility near the Weyl point in BiTeI

TL;DR

This paper investigates the unique disordered metallic state in BiTeI, revealing extreme mobility enhancement near the Weyl point and universal Hall resistivity scaling, highlighting complex electron interactions beyond simple models.

Contribution

It introduces the concept of diffusive helical Fermi liquid in BiTeI and demonstrates the limitations of the independent electron approximation in explaining Hall resistivity scaling.

Findings

Extreme disparity of mobility between Fermi surfaces near Weyl point

Universal scaling behavior observed in Hall resistivity

Breakdown of the independent electron picture indicating mass renormalization

Abstract

We show experimental and theoretical evidence that BiTeI hosts a novel disordered metallic state named diffusive helical Fermi liquid (DHFL), characterized by a pair of concentric spin-chiral Fermi surfaces with negligible inter-valley scattering. Key experimental observations are extreme disparity of the mobility between inner and outer helical Fermi surfaces near the Weyl point and existence of the so called universal scaling behavior for the Hall resistivity. Although the extreme enhancement of the inner-Fermi-surface mobility near the Weyl point is quantitatively explained within the self-consistent Born approximation, the existence of universal scaling in the Hall resistivity shows its breakdown, implying necessity of mass renormalization in the inner Fermi-surface beyond the independent electron picture.