Phenomenological model for magnetotransport in a multi-orbital system

By means of the Boltzmann equation, we have calculated some magnetotransport quantities for the layered multi-orbital compound Sr$_2$RuO$_4$. The Hall coefficient, the magnetoresistance and the in-plane resistivity have been determined taking into account the Fermi surface curvature and different time collisions for the electrons in the $t_{2g}$ bands. A consistent explanation of the experimental results has been obtained assuming different relaxation rates for the in-plane transport with and without an applied magnetic field, respectively.Comment: 4 pages, 3 Figure; to appear in Phys. Rev.

Curvature-induced Rashba spin-orbit interaction in strain-driven nanostructures

We derive the effective dimensionally reduced Schr\"odinger equation with spin-orbit interaction in low-dimensional electronic strain driven nanostructures. A method of adiabatic separation among fast normal quantum degrees of freedom and slow tangential quantum degrees of freedom is used to show the emergence of a strain-induced Rashba-like spin-orbit interaction (SOI). By applying this analysis to one-dimensional curved quantum wires we demonstrate that the curvature-induced Rashba SOI leads to enhanced spin-orbit effects.Comment: 5 pages, 3 figures, to be published in SPIN (World Scientific) as Topical Issue on Functional Nanomembrane

Edge states and topological insulating phases generated by curving a nanowire with Rashba spin-orbit coupling

We prove that curvature effects in low-dimensional nanomaterials can promote the generation of topological states of matter by considering the paradigmatic example of quantum wires with Rashba spin-orbit coupling, which are periodically corrugated at the nanometer scale. The effect of the periodic curvature generally results in the appearance of insulating phases with a corresponding novel butterfly spectrum characterized by the formation of fine measure complex regions of forbidden energies. When the Fermi energy lies in the gaps, the system displays localized end states protected by topology. We further show that for certain corrugation periods the system possesses topologically non-trivial insulating phases at half-filling. Our results suggest that the local curvature and the topology of the electronic states are inextricably intertwined in geometrically deformed nanomaterials.Comment: 5 pages, 5 figure

Magnetic-Field-Induced Topological Reorganization of a P-wave Superconductor

In this work we illustrate the detrimental impact of the Cooper pair's spin-structure on the thermodynamic and topological properties of a spin-triplet superconductor in an applied Zeeman field. We particularly focus on the paradigmatic one-dimensional case (Kitaev chain) for which we self-consistently retrieve the energetically preferred Cooper pair spin-state in terms of the corresponding spin d-vector. The latter undergoes a substantial angular and amplitude reorganization upon the variation of the strength and the orientation of the field and results to a modification of the bulk topological phase diagram. Markedly, when addressing the open chain we find that the orientation of the d-vector varies spatially near the boundary, affecting in this manner the appearance of Majorana fermions at the edge or even altering the properties of the bulk region. Our analysis reveals the limitations and breakdown of the bulk-boundary correspondence in interacting topological systems.Comment: 5 pages, 3 panels of figures; Minor corrections in the new version, which will appear in Phys. Rev. B as a Rapid Communicatio