$g$-factor engineering with InAsSb alloys toward zero band gap limit

TL;DR

This study demonstrates the engineering of large $g$-factors in InAsSb alloys near zero band gap, revealing a potential for gigantic $g$-factors and novel relativistic effects that surpass conventional models.

Contribution

It introduces high-quality InAsSb alloys with tunable $g$-factors and uncovers a new relativistic Zeeman effect near the zero gap limit, expanding understanding of spin properties in narrow-gap semiconductors.

Findings

Achieved a $g$-factor of approximately -90 at 0.1 eV band gap.

Predicted a possible $g$-factor of around -200 near zero gap.

Discovered a relativistic Zeeman effect dispersing as the square root of magnetic field.

Abstract

Band gap is known as an effective parameter for tuning the Lande $g$-factor in semiconductors and can be manipulated in a wide range through the bowing effect in ternary alloys. In this work, using the recently developed virtual substrate technique, high-quality InAsSb alloys throughout the whole Sb composition range are fabricated and a large $g$-factor of $g\approx -90$ at the minimum band gap of $\sim 0.1$ eV, which is almost twice that in bulk InSb is found. Further analysis to the zero gap limit reveals a possible gigantic $g$-factor of $g\approx -200$ with a peculiar relativistic Zeeman effect that disperses as the square root of magnetic field. Such a $g$-factor enhancement toward the narrow gap limit cannot be quantitatively described by the conventional Roth formula, as the orbital interaction effect between the nearly triply degenerated bands becomes the dominant source for the Zeeman splitting. These results may provide new insights into realizing large $g$-factors and spin polarized states in semiconductors and topological materials.