Speaker
Description
The Non-Linear Hall Effect (NLHE) represents a novel class of Hall-like phenomena that emerge without the need for time-reversal symmetry breaking, distinguishing it from conventional Hall effects. It consists of a transverse electric response which has a second-order contribution on the applied longitudinal current and arises from both intrinsic and extrinsic contributions. The intrinsic contribution is connected to the Berry curvature dipole (BCD), while the extrinsic contribution arises from the scattering sources in the system.
This study explores how this second-order response manifests in time-reversal invariant and inversion-breaking materials when subjected to an external electric field. Using semiclassical Boltzmann transport theory within the framework of the tilted 2D massive Dirac model, we investigate the influence of impurity scattering and electron–phonon interactions, allowing us to study the effect of temperature variation. To establish a realistic physical origin for the tilt parameter, we derive the effect of uniaxial strain within a tight-binding framework and show that strain can effectively be interpreted as a tilt parameter in the low-energy Dirac Hamiltonian. Different strain percentages are considered to evaluate how experimentally accessible strain conditions can modify the electronic structure and influence the NLHE.
Experimentally, a modified conventional Hall setup with an AC current and lock-in amplifiers is employed to study Bi$_2$Se$_3$ samples. This study opens new pathways for investigating the topological and symmetry properties of emergent quantum materials.