Field-direction control of the type of charge carriers in nonsymmorphic IrO2

TL;DR

This study demonstrates that in nonsymmorphic IrO2, the dominant charge carrier type can be intrinsically switched by changing the magnetic field direction, due to anisotropic Fermi surface properties.

Contribution

We experimentally and theoretically show field-direction control of charge carrier type in nonsymmorphic IrO2 through growth, Hall measurements, and first-principles calculations.

Findings

Carrier type switches with magnetic field orientation.

Anisotropic Fermi surfaces influence charge transport.

First-principles calculations support experimental results.

Abstract

In the quest for switching of the charge carrier type in conductive materials, we focus on nonsymmorphic crystals, which are expected to have highly anisotropic folded Fermi surfaces due to the symmetry requirements. Following simple tight-binding model simulation, we prepare nonsymmorphic IrO2 single-crystalline films with various growth orientations by molecular beam epitaxy, and systematically quantify their Hall effect for the corresponding field directions. The results clearly demonstrate that the dominant carrier type can be intrinsically controlled by the magnetic field direction, as also evidenced by first-principles calculations revealing nontrivial momentum dependence of the group velocity and mass tensor on the folded Fermi surfaces and its anisotropic nature for the field direction.