Possible origin of extremely large magnetoresistance in the topological insulator CaBi2 single crystal

TL;DR

This study investigates the magneto-transport properties of CaBi2, a topological insulator and superconductor, revealing extremely large magnetoresistance likely due to carrier compensation effects.

Contribution

It provides the first detailed experimental analysis of CaBi2's transport properties, highlighting its large magnetoresistance and underlying mechanisms.

Findings

Achieved ~15000% magnetoresistance at 3 K and 12 T.

Observed magnetic-field-induced resistivity upturn and plateau.

Confirmed compensation effect via Hall measurements.

Abstract

CaBi2 has been experimentally found to be a superconductor with a transition temperature of 2 K and identified as a topological insulator via spin- and angle-resolved photoemission spectroscopy, which makes it a possible platform to study the interplay between superconductivity and topology. But the detailed transport properties for CaBi2 single crystal remain unexplored in experiments. Here, we systematically studied the magneto-transport properties of CaBi2 single crystal grown by a flux method. CaBi2 shows a magnetic-field-induced upturn behavior with a plateau in resistivity at low temperature. An extremely large and non-saturating magnetoresistance up to ~15000% at 3 K and 12 T was achieved. The possible reason for the magnetic field and temperature dependence of resistivity and extremely large magnetoresistance at low temperature was discussed by adopting the Kohler's scaling law, which can be understood by the compensation effect confirmed by the Hall Effect measurement.