Band dependence of charge density wave in quasi-one-dimensional Ta2NiSe7 probed by orbital magnetoresistance

TL;DR

This study investigates how the charge density wave in Ta2NiSe7 affects its transport properties, revealing a suppression of hole density and the dominance of Se p orbitals in the CDW state through magnetoresistance measurements.

Contribution

It provides the first detailed analysis of the transport property changes and orbital contributions associated with the CDW transition in Ta2NiSe7.

Findings

Kohler's rule breaks down in the CDW state

Field dependence of MR shows a curvature change

Hole density is strongly suppressed in the CDW state

Abstract

Ta2NiSe7 is a quasi-one-dimensional (quasi-1D) transition-metal chalcogenide with Ta and Ni chain structure. An incommensurate charge-density wave (CDW) in this quasi-1D structure was well studied previously using tunnelling spectrum, X-ray and electron diffraction, whereas its transport property and the relation to the underlying electronic states remain to be explored. Here we report our results of magnetoresistance (MR) on Ta2NiSe7. A breakdown of the Kohler's rule is found upon entering the CDW state. Concomitantly, a clear change of curvature in the field dependence of MR is observed. We show that the curvature change is well described by two-band orbital MR, with the hole density being strongly suppressed in the CDW state, indicating that the $p$ orbitals from Se atoms dominate the change in transport through the CDW transition.