ZHAO, XG , CHINA CTR ADV SCI & TECHNOL,WORLD LAB,POB 8730,BEIJING 100080,PEOPLES R CHINA.
部门归属:
ACAD SINICA,INST THEORET PHYS,BEIJING 100080,PEOPLES R CHINA
英文摘要:
A formula for calculating the interband matrix elements of X for a Bloch electron in a uniform electric field is derived, from which it is found that the interband matrix elements of X are only determined by the interband matrix elements of the derivative of the periodic potential. Using this formula with a Kronig-Penney potential leads to nonvanishing interband matrix elements of X in a general setting, which implies that the exact Stark-ladder structure cannot exist in solids.
