Charge and Spin Transport in Dilute Magnetic Semiconductors
This proposal to the DOE outlines a three-year plan of research in theoretical and computational condensed-matter physics, with the aim of developing a microscopic theory for charge and spin dynamics in disordered materials with magnetic impurities. Important representatives of this class of materials are the dilute magnetic semiconductors (DMS), which have attracted great attention as a promising basis for spintronics devices. There is an intense experimental effort underway to study the transport properties of ferromagnetic DMS such as (Ga,Mn)As, and a number of interesting features have emerged: negative magnetoresistance, anomalous Hall effect, non-Drude dynamical conductivity, and resistivity maxima at the Curie temperature. Available theories have been able to account for some of these features, but at present we are still far away from a systematic microscopic understanding of transport in DMS. We propose to address this challenge by developing a theory of charge and spin dynamics based on a combination of the memory-function formalism and time-dependent density functional theory. This approach will be capable of dealing with two important issues: (a) the strong degree of correlated disorder in DMS, close to the localization transition (which invalidates the usual relaxation-time approximation to the Boltzmann equation), (b) the essentially unknown role of dynamical many-body effects such as spin Coulomb drag. We will calculate static and dynamical conductivities in DMS as functions of magnetic order and carrier density, which will advance our understanding of recent transport and infrared absorption measurements. Furthermore, we will study collective plasmon excitations in DMS (3D, 2D and quantum wells), whose linewidths could constitute a new experimental probe of the correlation of disorder, many-body effects and charge and spin dynamics in these materials.
- Research Organization:
- University of Missouri-Rolla, Rolla, MO; University of Missouri-Columbia, Columbia, MO
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- FG02-04ER46151
- OSTI ID:
- 960296
- Report Number(s):
- DOE/ER/46151-1 Final Report; TRN: US1100204
- Country of Publication:
- United States
- Language:
- English
Similar Records
Nonequilibrium spin transport through a diluted magnetic semiconductor quantum dot system with noncollinear magnetization
Mechanisms of interfacial reactivity in near surface and extreme environments
Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
APPROXIMATIONS
CARRIER DENSITY
CURIE POINT
FUNCTIONALS
HALL EFFECT
IMPURITIES
MAGNETIC SEMICONDUCTORS
MAGNETORESISTANCE
PHYSICS
PLASMONS
PROBES
RELAXATION TIME
SPIN
TRANSPORT
Spintronics
dilute magnetic semiconductors
spin transport
spin-density excitations
density-functional theory