Approaching the Type-II Dirac Point and Concomitant Superconductivity in Pt-doping Stabilized Metastable 1T-phase IrTe2

TL;DR

This paper reports the stabilization of a metastable 1T phase of IrTe2 through Pt doping, revealing a type-II Dirac semimetal with potential for topological superconductivity and Majorana devices.

Contribution

It demonstrates the tuning of Fermi level to the Dirac point in IrTe2 via Pt doping, revealing a type-II Dirac cone and associated superconductivity in a metastable phase.

Findings

Type-II Dirac cone observed in Ir1-xPtxTe2

Superconductivity occurs near the Dirac point

Fermi surface formed by a single tilted Dirac band

Abstract

Topological semimetal is a topic of general interest in material science. Recently, a new kind of topological semimetal called type-II Dirac semimetal with tilted Dirac cones is discovered in PtSe2 family. However, the further investigation is hindered due to the huge energy difference from Dirac points to Fermi level and the irrelevant conducting pockets at Fermi surface. Here we characterize the optimized type-II Dirac dispersions in a metastable 1T phase of IrTe2. Our strategy of Pt doping protects the metastable 1T phase in low temperature and tunes the Fermi level to the Dirac point. As demonstrated by angle-resolved photoemission spectra and first principle calculations, the Fermi surface of Ir1-xPtxTe2 is formed by only a single band with type-II Dirac cone which is tilted strongly along kz momentum direction. Interesting superconductivity is observed in samples for Dirac point close to Fermi level and even survives when Fermi level aligns with the Dirac point as finite density of states created by the tilted cone dispersion. This advantage offers opportunities for possible topological superconductivity and versatile Majorana devices in type-II Dirac semimetals.