Tuning the scattering mechanism in three-dimensional Dirac semimetal Cd$_{3}$As$_{2}$

TL;DR

This study investigates how magnetic field and doping influence charge scattering in the 3D Dirac semimetal Cd$_{3}$As$_{2}$, revealing tunable scattering mechanisms and their effects on electronic properties.

Contribution

It demonstrates the ability to tune charge scattering mechanisms in Cd$_{3}$As$_{2}$ through magnetic field and In doping, providing insights into the scattering behavior of 3D Dirac fermions.

Findings

Scattering time transitions from energy-independent to linear dependence with magnetic field.

In doping modifies the Fermi surface and scattering regimes.

Large magnetoresistance persists despite suppression of Shubnikov-de Haas oscillations.

Abstract

To probe the charge scattering mechanism in Cd$_{3}$As$_{2}$ single crystal, we have analyzed the temperature and magnetic field dependence of the Seebeck coefficient ($S$). The large saturation value of $S$ at high field clearly demonstrates the linear energy dispersion of three-dimensional Dirac fermion. A wide tunability of the charge scattering mechanism has been realized by varying the strength of the magnetic field and carrier density via In doping. With the increase in magnetic field, the scattering time crosses over from being nearly energy independent to a regime of linear dependence. On the other hand, the scattering time enters into the inverse energy-dependent regime and the Fermi surface strongly modifies with 2\% In doping at Cd site. With further increase in In content from 2 to 4\%, we did not observe any Shubnikov-de Haas oscillation up to 9 T field, but the magnetoresistance is found to be quite large as in the case of undoped sample.