Influence of Dirac cone warping and tilting on the Friedel oscillations in a topological insulator
We calculate the Ruderman-Kittel-Kasuya-Yosida interaction between impurity spins, localized at the surface of an imperfect topological insulator (TI). Namely, we consider the warping and tilting of a TI Dirac cone. We show that the warping and tilting addition to the initial Rashba spin-orbit interaction (SOI) yields a highly anisotropic response to the localized spin rotation. Also, the Friedel oscillation strength of such an imperfect TI depends on the direction in its plane. Latter dependence, parametrized by Lissajous curves of spin-response components, can serve as a “fingerprint” of the initial Dirac cone distortion in the TI. The ensuing unusual dynamics is due to the interplay of S…
Macroscopic description of the two-dimensionalLaAlO3/SrTiO3interface
We propose a simple analytical model to explain the possible appearance of the metallic conductivity in the two-dimensional (2D) ${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ interface. Our model considers the interface within a macroscopic approach, which is usual for semiconductor heterojunctions and is based on drift-diffusion equations. The solution of these equations allows us to obtain the positions of band edges as a function of distances from the interface. We show that for the 2D metallic conductivity to appear at the interface, the constituting substances should have the same type (either electronic or hole) of conductivity; in the opposite case the possible transition to metallic p…
Conductivity of the two-dimensional electron gas atLaAlO3/SrTiO3interface
We propose an analytical theory of metallic conductivity in the two-dimensional (2D) ${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ (LAO/STO) interface. For that we consider the electron-phonon interaction at the interface. The electronic part is taken from our previous work [Phys. Chem. Chem. Phys. 18, 2104 (2016)], considering the conditions for the interfacial charge carrier (electron or hole) to become itinerant. The second ingredient deals with the atomic oscillations localized near the interface and decaying rapidly at its both sides, which can be regarded as 2D acoustic phonons. The dispersion of such phonons depends on the characteristics of phonon spectra of LAO and STO. Calculating t…