Probing Electronic Structure of Weyl Semimetal using nanoARPES

Topological quantum materials exhibit a rich variety of electronic phases that can evolve dramatically with reduced dimensionality. In particular, materials that host Weyl semimetal (WSM) states in the bulk may transition to quantum spin Hall (QSH) insulating phases in the monolayer limit, providing a compelling platform for exploring two dimensional topological phenomena. Recently, TaIrTe₄ has emerged as an intriguing WSM candidate with exotic surface states, and its monolayer form has been shown in transport measurements to exhibit a dual QSH insulating state.

In this talk, I will present direct measurements of the electronic structure of monolayer TaIrTe₄ using angle-resolved photoemission spectroscopy with nanoscale spatial resolution (nanoARPES). I will also discuss the evolution of the band dispersion under electrostatic gating in device geometry and electron doping via alkali-metal deposition during ARPES experiments. The experimentally measured band structure shows excellent agreement with density functional theory (DFT) calculations performed using the Heyd–Scuseria–Ernzerhof (HSE) hybrid functional.