title: Bipolar magnetic semiconductors: a new class of spintronics materials.
abstract: Electrical control of spin polarization is very desirable in spintronics, since electric fields can be easily applied locally, in contrast to magnetic fields. Here, we propose a new concept of bipolar magnetic semiconductors (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. BMS is thus expected to have potential for various applications. 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.
authors.affiliation: Hefei National Laboratory of Physical Science at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Xingxing
authors.initials: X
authors.lastname: Li
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wu
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Li
authors.forename: Jinlong
authors.initials: J
authors.lastname: Yang
authors.forename: J G
authors.initials: JG
authors.lastname: Hou