Helical modes and Majorana end states in interacting nanowires   

2011-12-11 - 2011-12-13

D. Loss

5th International Workshop on Solid-State Quantum Computing, The Chinese University of Hong Kong, China

Helical modes, conducting opposite spins in opposite directions, are shown to exist in metallic armchair nanotubes in an all-electric setup [1] and in SiGe nanowires [2]. This is a consequence of the interplay between spin orbit interaction and strong electric fields. The helical regime can also be obtained in chiral metallic nanotubes by applying an additional magnetic field. In particular, it is possible to obtain helical modes at one of the two Dirac points only, while the other one remains gapped. Helical modes naturally lead to spin filtering, but they have also potential application as Cooper pair splitters [3] and, if in proximity with a superconductor, lead to Majorana bound states at the edges of the conductor. Helical modes have also attracted much attention recently in the context of topological insulators. I will then discuss Majorana end states in such systems and the interplay between interaction effects and proximity induced superconductivity in one-dimensional systems in terms of Luttinger liquids