Thermal tuning of the carrier density in Dirac semimetal Cd3As2 nanoplates

TL;DR

This study demonstrates that thermal treatment effectively tunes the carrier density and mobility in Cd3As2 Dirac semimetal nanoplates, revealing changes in electronic topology and surface states, thus offering a thermal control method for quantum state manipulation.

Contribution

We show that in-situ thermal treatment can non-monotonically tune carrier density and mobility in Cd3As2 nanoplates, affecting their topological and quantum transport properties.

Findings

Carrier density and mobility are tunable by thermal cycling.

Fermi level shifts affect surface Fermi-arc states.

Magnetoresistivity oscillations are coupled to surface states.

Abstract

The tunable carrier density plays a key role in the investigation of novel transport properties in three-dimensional topological semimetals. Here we demonstrate that the carrier density as well as the mobility of Dirac semimetal Cd3As2 nanoplates can be effectively tuned by the in-situ thermal treatment at 350 K for one hour, both showing a non-monotonic evolution with the thermal cycling treatments. The upward shift of Fermi level relative to the Dirac nodes blurs the surface Fermi-arc states, accompanying with an anomalous phase shift of oscillations of bulk states due to the change of topology of electrons. Meanwhile, the peaks of oscillations of bulk longitudinal magnetoresistivity shift at high fields due to their coupling to the oscillations of the surface Fermi-arc states. Our work provides a thermal control knob for manipulations of the quantum states through the carrier density in Dirac semimetal Cd3As2 at high temperature.