물리학과

In this talk, we will discuss tunable Hall effects in two different types of materials, magnetic metals and non-magnetic metals exhibiting anomalous Hall effect (AHE) and non-linear Hall effect (NLHE), respectively. In the first part of the talk, the AHE of CoS₂ is discussed, which is empirically assessed by manipulating the chemical potential through Fe- (hole) and Ni- (electron) doping. The primary mechanism underlying the colossal anomalous Hall conductivity (AHC) is identified through the application of density functional theory and tight-binding analyses. The main source of this substantial AHC of a value of 2507 Ω⁻¹cm⁻¹ is contributed from the four BC hotspots from gapped band crossings, all of which exhibit the same sign, a consequence of the d-wave-like spin-orbit coupling among spin-polarized eg orbitals. For the second part of the talk, we present NLHE realized in NbIrTe4 that persists above room temperature, coupled with a sign change in the Hall conductivity at 150 K. First-principles calculations combined with angle-resolved photoemission spectroscopy (ARPES) measurements show that the Berry curvature dipole tuned by the partial occupancy of spin-orbit split bands via temperature is responsible for the temperature-dependent NLHE. These findings highlight the correlation between BCD and the electronic band structure, providing a viable route to create and engineer the non-trivial Hall effect by tuning the geometric properties of quasiparticles in transition-metal chalcogen compounds.