The origin of the turn-on phenomenon in Td-MoTe2

TL;DR

This study investigates the origin of the turn-on phenomenon in Td-MoTe2 through resistivity and STM/STS experiments, revealing a correlation with electronic structure and magnetic field effects, and discusses its universality in extreme magnetoresistance materials.

Contribution

It provides new insights into the electronic and magnetic mechanisms behind the turn-on phenomenon in Td-MoTe2, including the role of electron-hole compensation and phase transitions.

Findings

Magnetoresistance follows Kohler rule scaling with m ≈ 1.92.

Turn-on temperature scales with magnetic field as T ∝ (H - Hc)^{1/2}.

STS shows minimal change under magnetic fields up to 7 T.

Abstract

We did the resistivity and scanning tunneling microscope/spectroscopy (STM/STS) experiments at different temperatures and magnetic fields to investigate the origin of the turn-on (t-o) phenomenon of Td-MoTe2. There are two interesting observations. Firstly, magnetoresistance (MR) follows the Kohler rule scaling: MR - (H/p0)m with m - 1.92 and the t-o temperature T under different magnetic fields can also be scaled by T - (H-Hc)u with u = 1/2. Secondly, a combination of compensated electron-hole pockets and a possible electronic structure phase transition induced by the temperature have been validated in Td-MoTe2 by the STM/STS experiments. Compared with the STS of Td-MoTe2 single crystal under H = 0, the STS hardly changes even when the applied field is up to 7 T. The origins of the t-o phenomenon in Td-MoTe2 are discussed. Meanwhile, we analyzed the universality and applicability of the t-o phenomenon in the extreme MR materials with almost balanced hole and electron densities as well as with other systems where the density of hole or electron is in dominant position.