Surface states, Friedel oscillations, and spin accumulation inp-doped semiconductors

2006/06/27 by Tudor D. Stanescu, Victor Galitski
Engineering · Mathematics · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #Condensed matter physics #Electron #Fermi surface #Friedel oscillations #Hamiltonian (control theory) #Luttinger liquid #Mathematics #Physics #Quantum and electron transport phenomena #Quantum mechanics #Semiconductor Quantum Structures and Devices #Spin (aerodynamics) #cond-mat.dis-nn #cond-mat.mtrl-sci

paper · pdf · doi:10.1103/physrevb.74.205331

published as Phys. Rev. B 74, 205331 (2006). · 22 pages, 8 color figures

arxiv created 2006/06/27 · openalex publication_date 2006/11/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We consider a hole-doped semiconductor with a sharp boundary and study the boundary spin accumulation in response to a charge current. First, we solve exactly a single-particle quantum-mechanics problem described by the isotropic Luttinger model in half-space and construct an orthonormal basis for the corresponding Hamiltonian. It is shown that the complete basis includes two types of eigenstates. The first class of states contains conventional incident and reflected waves, while the other class includes localized surface states. Second, we consider a many-body system in the presence of a charge current flowing parallel to the boundary. It is shown that the localized states contribute to spin accumulation near the surface. We also show that the spin density exhibits current-induced Friedel oscillations with three different periods determined by the Fermi momenta of the light and heavy holes. We find an exact asymptotic expression for the Friedel oscillations far from the boundary. We also calculate numerically the spin density profile and compute the total spin accumulation, which is defined as the integral of the spin density in the direction perpendicular to the boundary. The total spin accumulation is shown to fit very well the simple formula S_tot\ensuremath∝(1\ensuremath-m_L∕m_H)², where m_L and m_H are the light- and heavy-hole masses. The effects of disorder are discussed. We estimate the spin relaxation time in the Luttinger model and argue that spin physics cannot be described within the diffusion approximation.

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