Electronic Transport Phenomena in Low Dimensional and Topological Materials

Abstract

This dissertation focuses on electron transport properties in topologically nontrivial conductors (chiral p-wave superconductor Sr₂RuO₄ and stackings of van der Waals solids(vdWs)) and topological material, Weyl semimetals. Chiral p-wave superconductors exhibit spontaneous time reversal symmetry breaking due to the unconventional pairing order parameter. Violation of time reversal symmetry should manifest itself in anomalous transport effects analogous to anomalous Hall effect in ferromagnetic metals. We develop a semiclassical transport theory of several such effects: anomalous Hall effect, anomalous thermal Hall conductivity and polar Kerr effect for microwave radiation. The photogalvanic effects are studied in the van der Waals solids. Our findings predict a novel mechanism generating polarization dependent photocurrent in polar stacking of vdWs. This mechanism is attributed to the presence of a permanent electric dipole moment in the polar stacks. The recently discovered class of topological conductors, Weyl semimetals, is known for its novel surface electronic states and negative magnetoresistance (MR) due to chiral anomaly. We demonstrate that the interplay of band bending effects near the surface of the crystal and topological properties of Weyl points lead to spiral structure of energy dispersions for surface states. We also show that the interplay of chiral anomaly and Klein tunneling yields linear and negative MR of a WSM p-n junction, in contrast to positive MR in a conventional semiconductor p-n junction.