Theory of microwave absorption of 2dimensional Wigner crystals
Project/Area Number  10640307 
Research Category 
GrantinAid for Scientific Research (C)

Allocation Type  Singleyear Grants 
Section  一般 
Research Field 
固体物性I(光物性・半導体・誘電体)

Research Institution  Osaka University 
Principal Investigator 
SAITOH Motohiko Graduate School of Science, Osaka University Professor, 大学院・理学研究科, 教授 (80012441)

Project Period (FY) 
1998 – 1999

Project Status 
Completed(Fiscal Year 1999)

Budget Amount *help 
¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1999 : ¥500,000 (Direct Cost : ¥500,000)

Keywords  Wigner crystals / twodimensional electrons / plasma resonance / microwave absorption / ripplons / liquid helium surface / 電子局在 / ウィグナーフォノン 
Research Abstract 
1.It is pointed out that 2dimensional electrons located at the interface of semiconductor heterostructures such as SiMOS experience the localizeddelocalized transition by the influence of impurities in oxides. We have shown by using the pathintegral formalism that when electrons form an electron crystal or Wigner lattice, the Wigner phonon spectra have an energy gap in the long wavelength limit, and that the electrons are localized. The lineshape of the microwave absorption is not of the Lorentzian type but asymmetric owing to the density of states of the Wigner phonons. 2.Kono et al. measured the plasmon resonance of quasi2dimensional electrons on liquid helium 3 at very low temperatures and found that (a) the resonance position is almost independent of temperature, and (b) the linewidth is roughly proportional to temperature. By assuming that the 2dimensional electrons form a Wigner crystal which interacts with the surface capillary waves or ripplons of liquid helium, we have calculated the linewidth of the plasmon resonance by the linear ac conductivity formula obtained by the pathintegral method. The results show that the linewidth is proportional to temperature and is in good agreement with experiments. This temperature dependence comes from the number of scatterers, i. e., of thermally excited ripplons.

Report
(3results)
Research Output
(7results)