Elucidation of Nonequilibrium Current Distributions of Semiconductor Quantum Wires in High Magnetic Fields
Project/Area Number  08640433 
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  Sendai National College of Technology 
Principal Investigator 
SUZUKI Tatsuo Sendai National College of Technology, Lecturer, 講師 (60270203)

Project Period (FY) 
1996 – 1997

Project Status 
Completed(Fiscal Year 1997)

Budget Amount *help 
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1997 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1996 : ¥2,000,000 (Direct Cost : ¥2,000,000)

Keywords  mesoscopic / ballistic / quantum wire / high magnetic field / nonequilibrium current / Boltzmann transport equation / inpurity scattering / quantum Hall effect / ボルツマン輸送方程式 
Research Abstract 
1.Fortran 77 programs which calculate noncquilibrium current distributions in term of Boltzmann transport equation have been developed, and the nonequilibrium current distributions about the electronic stetes of realistic semiconductor quantum wires in high magnetic fields were calculated. Collision terms include the elastic scattering of inpurities and the inelastic scattering of acoustic phonons. However these collision terms cannot maintain the steady state because the strength of the collision is too weak to cancel the drift of the center coordinate of the cyclotron motion. It is not yet clear that the description of Boltzmann transport equation is adequate, but I think the qualitative behavior is well expressed by Boltzmann transport equation. In future the scattering mechanism inside the degenerate states of Landau levels which causes Shubnikovde Hass effect will introduced, and the problem between the balk current and the edge current will be solved. 2.The electronic states of wide semiconductor quantum wires (up to 2mu m) in high magnetic fields (3.111.4T) at low temperatures (250 mK) have been calculated in a selfconsistent Hartree approximation. The electronic states in high magnetic fields be in special conditions that the Landau level like the delta function sticks to the Fermi energy, so the selfconsistent calculation became a very large scale beyond our expectations. Points of difference among the analytical theory of Chklovskii et al., the ThomasFermi approximationof Lier et al., and our Hartree approximation habe been clear. 3.Conductance in high magnetic fields has been calculated using the recursion method and Landauer transport theory. Calculations were done using an infinite hard wall potential, a parabolic potential, and a selfconsistent Hartree potential as the models of effective confining potential, and points of difference among the models have been clear.

Report
(3results)
Research Output
(6results)