Gate Controlled Spin-Orbit Interaction and 1D Thermoelectric Transport in InAs Nanowires – Xuan Gao

Date: Thu. September 13th, 2012, 4:15 pm-5:15 pm
Location: Rockefeller 301

InAs nanowires provide an interesting nanomaterial platform for spintronic device and thermoelectric energy conversion applications, owing to their strong quantum confinement and spin orbit interaction (SOI) effects. Manipulating the SOI and thermoelectric transport in InAs nanowires is thus of great interest for both fundamental quantum transport and applied nanotechnology research. First, we will discuss our recent results of gate induced generation and control of the Rashba SOI (a momentum dependent splitting of spin bands) in InAs nanowires, which is essential for the realization of many spintronic devices. Second, we present a study of the thermoelectric properties of InAs nanowires where the gate was used to sweep the electrons’ Fermi level through quantized one-dimensional (1D) subbands. At temperatures below about 100K, large oscillations in the thermopower and power factor concomitant with the stepwise conductance increases are observed due to the formation of 1D electron sub-bands. This work experimentally demonstrates the possibility to tailor a nanowire’s thermoelectric properties through a 1D quantum confinement effect, a long-sought goal in nanostructured thermoelectrics research.