EventDetails

Speaker:
Dr. Paramita Dutta, Institute of Physics, Bhubaneswar, India

Quantum Transport properties of a one-dimensional ring model with helical current will be discussed. The behavior of the helical ring with long-range hopping and characterized by zero energy crossings in theenergy spectrum is very much similiar to one-dimensionaledge states of a 2D tolological insulator. We apply Aharonov-Bohm flux in the two-terminal helical ring in presence of Rashba spin-orbit interaction and explore how the spin polarization behavior changes depending on the applied magnetic flux and the incoming electron energy. The morst interesting feature that we articulate in this system is that zero-energy crossing appear in the energy spectra at $\Phi=0$ and also at integer multiples of half-flux quantum values ($n\Phi_0/2$, n being an integer) of the applied magnetic flux. We investigate the transport properties of the ring using Green's function formalism and find that the zero energy transmission peaks corresponding to those zero energy crossings vanish in presence of Rashba spin-orbit interaction. we also incorporate static random disorder in pur system and show that the zero energy crossings and transmission peaks are not immune to disorder even in absence of Rashba spin-orbit interaction. The latter prevents the possibility of behaving thes helical states in the ring like topological insulator edge states.