Electronic collective modes and instabilities on semiconductor surfaces. I

Journal Article · Wed Aug 15 04:00:00 EDT 1984 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.30.1911· OSTI ID:6767634

Muramatsu, A; Hanke, W

A Green's-function theory of electronic collective modes is presented which leads to a practical scheme for a microscopic determination of surface elementary excitations in conducting as well as nonconducting solids. Particular emphasis is placed on semiconductor surfaces where the jellium approximation is not valid, due to the importance of density fluctuations on a microscopic scale (reflected in the local-field effects). Starting from the Bethe-Salpeter equation for the two-particle Green's function of the surface system, an equation of motion for the electron-hole pair is obtained. Its solutions determine the energy spectra, lifetimes, and amplitudes of the surface elementary excitations, i.e., surface plasmons, excitons, polaritons, and magnons. Exchange and correlation effects are taken into account through the random-phase and time-dependent Hartree-Fock (screened electron-hole attraction) approximations. The formalism is applied to the study of electronic (charge- and spin-density) instabilities at covalent semiconductor surfaces. Quantitative calculations for an eight-layer Si(111) slab display an instability of the ideal paramagnetic surface with respect to spin-density waves with wavelength nearly corresponding to (2 x 1) and (7 x 7) superstructures.

• Research Organization: Institute for Theoretical Physics, University of California, Santa Barbara, California 93106
• OSTI ID: 6767634
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 30:4; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
AMPLITUDES
COLLECTIVE EXCITATIONS
CRYSTAL FACES
DIFFERENTIAL EQUATIONS
ELECTRON-HOLE DROPLETS
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY SPECTRA
ENERGY-LEVEL TRANSITIONS
EQUATIONS
EQUATIONS OF MOTION
EXCITATION
FUNCTIONS
GREEN FUNCTION
INSTABILITY
LIFETIME
MATERIALS
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA
QUASI PARTICLES
SEMICONDUCTOR MATERIALS
SEMIMETALS
SILICON
SOLID-STATE PLASMA
SPECTRA