Carrier-density dependence of magnetotransport in correlated Dirac semimetal CaIrO$_3$

TL;DR

This study investigates how carrier density influences magnetotransport in the correlated Dirac semimetal CaIrO$_3$, revealing high mobility, large magnetoresistance, and the effects of Coulomb interactions on magnetoresistivity.

Contribution

It provides detailed analysis of magnetotransport properties across different carrier densities, supporting the $k$-linear dispersion of Dirac electrons in CaIrO$_3$.

Findings

High mobility exceeding 1.0 x 10^5 cm^2/Vs at low carrier density.

Magnetoresistance reaches 2000% at 12 T in dilute carrier density.

Magnetoresistivity behavior varies with carrier density, influenced by Coulomb interactions.

Abstract

We report the carrier density dependence of the magnetotransport property in the correlated Dirac semimetal CaIrO$_3$. In the dilute carrier density region ($n_{\rm H}$ $\sim 2.2 \times 10^{16} \,$$\rm{cm}^{-3}$) at $2 \, \mathrm{K}$, the mobility exceeds $1.0 \times 10^{5} \,$$\rm{cm}^{2}/\rm{Vs}$ at $2 \, \mathrm{K}$, and the transverse magnetoresistance (MR) reaches $2,000 \,$\% at $12 \, \mathrm{T}$. The analysis of quantum oscillations and Hall conductivity shows that the Fermi velocity is nearly independent of the cross-sectional area of the Fermi surface, or equivalently the carrier density, supporting a $k$-linear dispersion of the Dirac node. The field dependence of magnetoresistivity is nearly $B$-linear in the moderate carrier density region ($n_\mathrm{H} \geq 4 \times 10^{16}\,$cm$^{-3}$), but scales with $B^{\alpha}$ ($\alpha > 2$) in the lower carrier density region. The variation of magnetoresistivity is likely affected by the enhanced long-range Coulomb interaction in the quantum limit, where Dirac electrons are subject to the magnetic confinement.