Unusual strain relaxation and Dirac semimetallic behavior in epitaxial antiperovskite nitrides

TL;DR

This study reports the synthesis and characterization of Ni3InN epitaxial films, revealing strain-induced Dirac semimetallic behavior and strange-metal transport, highlighting their potential for exploring novel electronic phases.

Contribution

It demonstrates the successful epitaxial growth of Ni3InN thin films and uncovers their unique strain-dependent electronic properties, including Dirac-like bands and strange-metal behavior.

Findings

Epitaxial Ni3InN films exhibit coherent interfaces on certain substrates.

Strain controls Fermi-liquid behavior and band structure.

Presence of Dirac-like bands and strange-metal transport phenomena.

Abstract

Antiperovskite nitrides (X3AN) are the structural analogues to perovskite oxides, while their epitaxial growth and electronic properties remain largely unexplored. We report the successful synthesis of Ni3InN thin films on substrates with different lattice constants. First-principles phonon calculations confirm the dynamical stability of cubic phase Ni3InN, providing the basis for epitaxial synthesis. High-resolution scanning transmission electron microscopy reveals coherent (001)-oriented interfaces when Ni3InN is grown on LaAlO3 and SrTiO3, while an unexpected (011)-orientation forms on DyScO3, aligning with surface-energy predictions. Transport measurements highlight a strain-controlled Fermi-liquid behavior, correlated with variations in the Ni-3d bandwidth and hybridization. Band structure calculations reveal a dual character near the Fermi level: a high-mobility Dirac-like band and a Ni-3d manifold that drives strange-metal transport with a reduced slope compared to oxide perovskites. The formal Ni valence (+2/3) places Ni3InN in an overdoped correlated-metal regime, distinguishing from most perovskite oxides. This positions antiperovskite nitrides as a promising platform for investigating overdoped Fermi liquids and strange-metal behavior.