Near-half-metallic state in the half Heusler PtMnSb film on a III-V substrate

TL;DR

This study demonstrates the epitaxial growth of high-quality PtMnSb films on GaSb substrates, revealing a near-half-metallic state with high spin polarization, which advances the potential for spintronics applications in III-V semiconductor devices.

Contribution

First successful epitaxial growth and detailed electronic structure analysis of PtMnSb on III-V substrates, showing near-half-metallicity and high spin polarization at low temperatures.

Findings

PtMnSb exhibits a near-half-metallic state with both spin bands crossing the Fermi level.

High spin polarization over 90% is observed.

Anomalous magnetization enhancement occurs below 60 K.

Abstract

The interplay between half-metallic ferromagnetism and spin-orbit coupling within the inversion symmetry-broken structure of half Heuslers provides an ideal platform for various spintronics functionalities. Taking advantage of good lattice matching, it is highly desired to epitaxially integrate promising Heuslers into III-V semiconductor-based devices. PtMnSb is one of the first half Heuslers predicted to be an above-room-temperature half-metal with large spin orbit coupling, however, its half-metallicity and potential as a spintronics material has remained elusive due to lack of high quality samples. Here we demonstrate epitaxial growth of single crystal PtMnSb(001) film on GaSb(001) substrates using molecular beam epitaxy. Direct observation of the band structure via angle-resolved photoemission spectroscopy and many-body perturbation theory within the quasiparticle self-consistent GW approximation (QPGW) reveal that PtMnSb hosts rather a near-halfmetallic state with both spin bands crossing the Fermi level and with high spin polarization over 90%. Temperature dependence of magnetization also shows an anomalous enhancement below 60 K, which can be associated with the development of such a near-half-metallic state at low temperatures. Epitaxial growth of high crystalline PtMnSb on a III-V paves the way for systematic clarification of its spin transport properties with fine-tuning of strain in heterostructure devices.