Influence of Rashba spin-orbit coupling on the 0-π transition and Kondo temperature in one-dimensional superconductors

Abstract

Using the framework of the density-matrix renormalization group (DMRG), we study a quantum dot coupled to a superconducting nanowire with strong Rashba spin-orbit coupling. Regarding the singlet-to-doublet "0-π" transition that takes place when the Kondo effect is overcome by the superconducting gap, we show that the Rashba coupling modifies the critical values at which the transition occurs, favoring the doublet phase. In addition, using a generalized Haldane's formula for the Kondo temperature TK, we show that it is lowered by the Rashba coupling. We benchmark our DMRG results, comparing them with previous numerical renormalization group results. The good agreement obtained opens the possibility of studying chains or clusters of impurities coupled to superconductors by means of DMRG.