磁场对二维量子点两电子系统自旋极化态能级的影响

Influence of Magnetic Field on the Energy of Spin Polarization State of the Two-electron System in Two-dimensional Quantum Dot

采用少体物理方法,研究了磁场对二维量子点两电子系统自旋极化态能级的影响。以GaAs半导体量子点为例,对体系基态能级E0、第一激发态自旋单态能级E1(A)和自旋三重态能级E1(S)随量子点有效半径l0和磁场B的变化进行了数值计算。结果表明,E0随B的增加而增大,随l0的增加而减小;在磁场中第一激发态自旋单态能级E1(A)分裂为E1+1(A)、E1-1(A)两条,第一激发态自旋三重态能级E1(S)分裂为EMS1+1(S)、EMS1-1(S)(MS=1,0,-1)两组,每组中有三条"精细结构";各能级(组)均随l0的增加而减小,而它们随B的变化情况差异较大,能级E1+1(A)和EMS1+1(S)随B的增加而显著增大,而能级E1-1(A)和EMS1-1(S)随B的变化相对缓慢;各能级(组)的分裂度均与磁场B的一次方成正比。

Influence of magnetic field on the energy of spin polarization state of two-electron system in two-dimensional quantum dot is studied by using the method of few-body physics. As an example, the numerical calculation is performed for GaAs semiconductor quantum dot to show the variations of the ground-state energy E0, spin-singlet energy E1 （A） and spin-triplet energy E1 （S） of first excited state with the effective radius 10 and the magnetic field B. The results of numerical calculation show that E0 increases with increasing B, but decreases with increasing 10 in the magnetic field, the spin-singlet energy El （A） of first excited state splits into two branches as E1＋1 （A） and El-1 （A）, and the spin-triplet energy El （S） of first excited state splits into two Ms sets as E^Ms1＋1 （S） and E^Ms1-1 （S） （where Ms= 1,0,- 1） , with each set consisting of three ＂fine struc- ture＂~ each energy （set） mentioned above decreases with increasing l0, but there are significant