Magnetism and metal-insulator transition in two-dimensional electron systems formed in semiconductor interfaces
Grant-in-Aid for Scientific Research on Priority Areas (B)
|Allocation Type||Single-year Grants|
|Research Institution||University of Tokyo(2000-2001)|
OKAMOTO Tohru University of Tokyo, Department of Physics, Graduate School of Science, Assistant Professor, 大学院・理学系研究科, 助教授 (60245371)
KAWAJI Shinji Gakushuin University, Department of Physics, Faculty of Science, Professor, 理学部, 教授 (00080440)
|Project Period (FY)
1998 – 2000
Completed(Fiscal Year 2001)
|Budget Amount *help
¥9,300,000 (Direct Cost : ¥9,300,000)
Fiscal Year 2000 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1999 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1998 : ¥7,500,000 (Direct Cost : ¥7,500,000)
|Keywords||two-dimensional electron systems / metal-insulator transition / electron correlation / Wigner solid / magnetoresistance|
We have studied electronic states and magnetic states in strongly correlated two-dimensional electron systems formed in Si-MOSFETs and Si/SiGe heterostructures.
1) We have measured the spin susceptibility as a function of the correlation parameter rs. The spin susceptibility monotonically increases with rs.
2) We found that the magnetoresistance in parallel magnetic fields is mainly caused by the spin polarization.
3) We observed the metallic phase even in the completely spin polarized system for a Si/SiGe heterostructure sample.
4) We have observed oscillations of the diagonal resistivity associated with the concentration of electrons having an up-spin.
5) We have established the process of making field-effect-transistor samples.
6) For comparison, we have investigated on the insulating phase in two-dimensional electron systems formed in GaAs/AlGaAs field-effect-transistor device, where the electron correlations are much weaker those in the silicon systems.
Research Output (13results)