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Title: Low-Energy Charge-Density Excitations in MgB2: Striking Interplay Between Single-Particle and Collective Behavior for Large Momenta

Abstract

A sharp feature in the charge-density excitation spectra of single-crystal MgB{sub 2}, displaying a remarkable cosinelike, periodic energy dispersion with momentum transfer (q) along the c* axis, has been observed for the first time by high-resolution nonresonant inelastic x-ray scattering (NIXS). Time-dependent density-functional theory calculations show that the physics underlying the NIXS data is strong coupling between single-particle and collective degrees of freedom, mediated by large crystal local-field effects. As a result, the small-q collective mode residing in the single-particle excitation gap of the B {pi} bands reappears periodically in higher Brillouin zones. The NIXS data thus embody a novel signature of the layered electronic structure of MgB{sub 2}.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930140
Report Number(s):
BNL-80793-2008-JA
Journal ID: ISSN 0031-9007; PRLTAO; TRN: US200822%%1200
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 97
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MAGNESIUM BORIDES; BRILLOUIN ZONES; CHARGE DENSITY; ELECTRONIC STRUCTURE; EXCITATION; MOMENTUM TRANSFER; INELASTIC SCATTERING; X-RAY DIFFRACTION; DENSITY FUNCTIONAL METHOD; national synchrotron light source

Citation Formats

Cai,Y., Chow, P., Restrepo, O., Takano, Y., Kito, H., Ishii, H., Chen, C., Liang, K., Chen, C., and et al.. Low-Energy Charge-Density Excitations in MgB2: Striking Interplay Between Single-Particle and Collective Behavior for Large Momenta. United States: N. p., 2006. Web. doi:10.1103/PhysRevLett.97.176402.
Cai,Y., Chow, P., Restrepo, O., Takano, Y., Kito, H., Ishii, H., Chen, C., Liang, K., Chen, C., & et al.. Low-Energy Charge-Density Excitations in MgB2: Striking Interplay Between Single-Particle and Collective Behavior for Large Momenta. United States. doi:10.1103/PhysRevLett.97.176402.
Cai,Y., Chow, P., Restrepo, O., Takano, Y., Kito, H., Ishii, H., Chen, C., Liang, K., Chen, C., and et al.. Sun . "Low-Energy Charge-Density Excitations in MgB2: Striking Interplay Between Single-Particle and Collective Behavior for Large Momenta". United States. doi:10.1103/PhysRevLett.97.176402.
@article{osti_930140,
title = {Low-Energy Charge-Density Excitations in MgB2: Striking Interplay Between Single-Particle and Collective Behavior for Large Momenta},
author = {Cai,Y. and Chow, P. and Restrepo, O. and Takano, Y. and Kito, H. and Ishii, H. and Chen, C. and Liang, K. and Chen, C. and et al.},
abstractNote = {A sharp feature in the charge-density excitation spectra of single-crystal MgB{sub 2}, displaying a remarkable cosinelike, periodic energy dispersion with momentum transfer (q) along the c* axis, has been observed for the first time by high-resolution nonresonant inelastic x-ray scattering (NIXS). Time-dependent density-functional theory calculations show that the physics underlying the NIXS data is strong coupling between single-particle and collective degrees of freedom, mediated by large crystal local-field effects. As a result, the small-q collective mode residing in the single-particle excitation gap of the B {pi} bands reappears periodically in higher Brillouin zones. The NIXS data thus embody a novel signature of the layered electronic structure of MgB{sub 2}.},
doi = {10.1103/PhysRevLett.97.176402},
journal = {Physical Review Letters},
number = ,
volume = 97,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}