Mitrofanovite Pt3Te4: A Topological Metal with Termination-Dependent Surface Band Structure and Strong Spin Polarization

Jun Fujii,Danil W Boukhvalov,Amit Agarwal,Barun Ghosh,Debashis Mondal,Lixue Zhang,Chia-Nung Kuo,Ivana Vobornik,Chin Shan Lue,Antonio Politano,Anan Bari Sarkar,François C Bocquet

doi:10.1021/acsnano.1c04766

Abstract

Due to their peculiar quasiparticle excitations, topological metals have high potential for applications in the fields of spintronics, catalysis, and superconductivity. Here, by combining spin- and angle-resolved photoemission spectroscopy, scanning tunneling microscopy/spectroscopy, and density functional theory, we discover surface-termination-dependent topological electronic states in the recently discovered mitrofanovite Pt3Te4. Mitrofanovite crystal is formed by alternating, van der Waals bound layers of Pt2Te2 and PtTe2. Our results demonstrate that mitrofanovite is a topological metal with termination-dependent (i) electronic band structure and (ii) spin texture. Despite their distinct electronic character, both surface terminations are characterized by electronic states exhibiting strong spin polarization with a node at the Γ point and sign reversal across the Γ point, indicating their topological nature and the possibility of realizing two distinct electronic configurations (both of them with topological features) on the surface of the same material.

Highlights

Topological metals are materials with nontrivial band crossings or band inversions near the Fermi energy, giving rise to peculiar quasiparticle excitations.[1−8] They can be classified based on the dimensionality and degeneracy of their band crossings.[9]
We demonstrate that mitrofanovite is a topological metal hosting spin-polarized surface states
As the energy per surface unit for the PtTeterminated slab is more than 1 eV larger than for the PtTe2and Pt2Te2-terminated slab, this type of termination can be excluded from further discussion

Summary

Introduction

Topological metals are materials with nontrivial band crossings or band inversions near the Fermi energy, giving rise to peculiar quasiparticle excitations.[1−8] They can be classified based on the dimensionality and degeneracy of their band crossings.[9]. Among the various families of materials showing gapless Dirac Fermions, the transition-metal dichalcogenide TMX2 (TM = Pd, Pt; X = Se, Te), crystallizing in the same structure as the naturally occurring mineral “moncheite”,16 was demonstrated to host type-II Dirac fermions,[17] with application capabilities in plasmonics,[10] catalysis,[18] nanoelectronics,[19] and wearable electronics.[20] These properties can be tuned by varying (i) the position of the Fermi level with respect to the degenerate Dirac (or Weyl/nodal line) point and (ii) the strength of the spin−orbit coupling

Methods

Results

Conclusion