The intrinsic quantum anomalous Hall effect in TaPdXTe (X = S, Se) monolayers†

The search for high-performance intrinsic quantum anomalous Hall (QAH) insulators is crucial for the development of topological electronics. Here, based on density–functional theory calculations, TaPdSTe and TaPdSeTe monolayers are demonstrated to be intrinsic QAH insulators with topological band gaps of 88 and 79 meV, respectively. Both TaPdSTe and TaPdSeTe monolayers show an out-of-plane magnetic anisotropy with the Curie temperatures of 260 and 262 K by Monte Carlo simulations, respectively. The calculated Chern number C for both materials is −1. The analysis of the electronic structures reveals that the ferromagnetic topological property is caused by the energy band inversions of d_xz and d_yz orbitals of Ta atoms. Additionally, the effects of biaxial strain on the magnetic and topological properties are discussed for the current TaPdSTe and TaPdSeTe monolayers. During −3 to 3% biaxial strains, TaPdSTe and TaPdSeTe monolayers maintain the QAH effect, but their topological band gaps increase gradually from compressive to tensile strains. This study presents two intrinsic topological insulators that can help develop low-power electronic devices.