title: Donor-driven spin relaxation in multivalley semiconductors.
abstract: The observed dependence of spin relaxation on the identity of the donor atom in n-type silicon has remained without explanation for decades and poses a long-standing open question with important consequences for modern spintronics. Taking into account the multivalley nature of the conduction band in silicon and germanium, we show that the spin-flip amplitude is dominated by short-range scattering off the central-cell potential of impurities after which the electron is transferred to a valley on a different axis in k space. Through symmetry arguments, we show that this spin-flip process can strongly affect the spin relaxation in all multivalley materials in which time-reversal cannot connect distinct valleys. From the physical insights gained from the theory, we provide guidelines to significantly enhance the spin lifetime in semiconductor spintronics devices.
authors.affiliation: Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.affiliation: Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627, USA.
authors.forename: Oleg
authors.initials: O
authors.lastname: Chalaev
authors.affiliation: Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627, USA and Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA.
authors.forename: Hanan
authors.initials: H
authors.lastname: Dery
mesh_terms: D008962:Models, Theoretical; D012666:Semiconductors; D012825:Silicon / Q000737:chemistry*
chemical_list: D012825:Silicon