title: Hall voltages without a magnetic field in a non-uniform two-dimensional electron system.
abstract: We report on a measurement of giant second-harmonic Hall voltages which occur without a magnetic field and do not change their sign on current reversal in a two-dimensional electron system with a transverse density gradient. A quadratic dependence on the electric field, a strong temperature dependence, and both magnitude and directional dependence on the magnetic field are also observed. Such behavior points towards a plausible explanation based on a novel spin Hall effect with in-plane spin polarization.
authors.affiliation: Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747, Korea. hnoh@sejong.ac.kr
authors.forename: Hwayong
authors.initials: H
authors.lastname: Noh
authors.forename: Seung-Jo
authors.initials: SJ
authors.lastname: Lee
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Chun