Fermi surface reconstruction and electron dynamics at the charge-density-wave transition in TiSe2

TL;DR

This study investigates how the Fermi surface and electron behavior in TiSe2 change during the charge-density-wave transition, revealing a sudden reconstruction and mobility minimum linked to CDW mode scattering.

Contribution

It provides detailed experimental insights into Fermi surface reconstruction and electron dynamics at the CDW transition in TiSe2, highlighting its role as a model system.

Findings

Abrupt Fermi surface reconstruction at the CDW transition

Minimum in electron and hole mobilities at transition

Dominance of a small electron pocket at low temperatures

Abstract

The evolution of the charge carrier concentrations and mobilities are examined across the charge-density-wave (CDW) transition in TiSe2. Combined quantum oscillation and magnetotransport measurements show that a small electron pocket dominates the electronic properties at low temperatures whilst an electron and hole pocket contribute at room temperature. At the CDW transition, an abrupt Fermi surface reconstruction and a minimum in the electron and hole mobilities are extracted from two-band and Kohler analysis of magnetotransport measurements. The minimum in the mobilities is associated with the overseen role of scattering from the softening CDW mode. With the carrier concentrations and dynamics dominated by the CDW and the associated bosonic mode, our results highlight TiSe2 as a prototypical system to study the Fermi surface reconstruction at a density-wave transition.