Electrical control of spin polarization is very desirable in spintronics, since electric field can be easily applied locally in contrast with magnetic field. Here, we propose a new concept of bipolar magnetic semiconductor (BMS) in which completely spin-polarized currents with reversible spin polarization can be created and controlled simply by applying a gate voltage. This is a result of the unique electronic structure of BMS, where the valence and conduction bands possess opposite spin polarization when approaching the Fermi level. Our band structure and spin-polarized electronic transport calculations on semi-hydrogenated single-walled carbon nanotubes confirm the existence of BMS materials and demonstrate the electrical control of spin-polarization in them.
@article{arxiv.1208.1355,
title = {Bipolar Magnetic Semiconductors: A New Class of Spintronics Materials},
author = {Xingxing Li and Xiaojun Wu and Zhenyu Li and Jinlong Yang and J. G. Hou},
journal= {arXiv preprint arXiv:1208.1355},
year = {2012}
}