Semiconductor Spintronics: Role of the Valence-Band Holes
نویسنده
چکیده
Two aspects related to valence-band hole spin are considered: spin surfaces in p-type semiconductors and flipping of the hole spin by an ultrashort electric field pulse. It is shown that heavy, light, and split-off holes have different spin surfaces. In general, the shape of the surface in real semiconductors may depend on the hole wave vector direction and magnitude. The concept of spin surface is used to explain very strong anisotropy of hole spin injection efficiency observed recently in ferromagnetic-semiconductor structures and in optimizing ultrafast spin switching. It was shown that, of all spin flipping mechanisms, the most effective one is associated with hole transfer between different spin surfaces in high electric fields. The less effective mechanisms are related to valence band warping and nonparabolicity. Examples of the hole spin flipping dynamics and the discussion on ultrafast control of spin in semiconductors by π-type electrical pulses are presented.
منابع مشابه
Controlling the Curie temperature in (Ga,Mn)As through location of the Fermi level within the impurity band.
The ferromagnetic semiconductor (Ga,Mn)As has emerged as the most studied material for prototype applications in semiconductor spintronics. Because ferromagnetism in (Ga,Mn)As is hole-mediated, the nature of the hole states has direct and crucial bearing on its Curie temperature T(C). It is vigorously debated, however, whether holes in (Ga,Mn)As reside in the valence band or in an impurity band...
متن کاملDielectric function of the semiconductor hole gas
The semiconductor hole gas can be viewed as the companion of the classic interacting electron gas with a more complicated band structure and plays a crucial role in the understanding of ferromagnetic semiconductors. Here we study the dielectric function of a homogeneous hole gas in zinc blende III–V bulk semiconductors within random phase approximation with the valence band being modeled by Lut...
متن کاملHot-electron photoluminescence study of the „Ga,Mn...As diluted magnetic semiconductor
We study the spectral shape and the magnetic field induced polarization of hot-electron photoluminescence from the diluted magnetic semiconductor Ga,Mn As. It is demonstrated that the holes occupy predominantly the impurity band and not the valence band as required for the Rudermann-Kittel-Kasuya-Yosida-type exchange interaction. We show that the ground state of the impurity band is split by un...
متن کاملSpin diffusion in doped semiconductors: the role of Coulomb interactions
– We examine the effect of Coulomb interaction on the mobility and diffusion of spin packets in doped semiconductors. We find that the diffusion constant is reduced, relative to its non-interacting value, by the combined effect of Coulomb-enhanced spin susceptibility and spin Coulomb drag. In ferromagnetic semiconductors, the spin diffusion constant vanishes at the ferromagnetic transition temp...
متن کاملAnalysis of the Band-Structure in (Ga, Mn)As Epitaxial Layers by Optical Methods
The ternary III-V semiconductor (Ga, Mn)As has recently drawn a lot of attention as the model diluted ferromagnetic semiconductor, combining semiconducting properties with magnetism. (Ga, Mn)As layers are usually gown by the low-temperature molecular-beam epitaxy (LT-MBE) technique. Below a magnetic transition temperature, TC, substitutional Mn2+ ions are ferromagnetically ordered owing to inte...
متن کامل