Wave functions and g factor of holes in Ge/Si quantum dots -: art. no. 205301

We investigate theoretically the Zeeman effect on the hole states in quantum dots. In frame of tight-binding approach, we propose a method of calculating the g factor for localized states. The principal values of the g factor for the ground hole state in the self-assembled Ge/Si quantum dot are calculated. We find the strong g-factor anisotropy-the components g(xx), g(yy) are one order smaller than the g(zz) component, g(zz)=12.28, g(xx)=0.69, g(yy)=1.59. The efficiency of the developed method is demonstrated by calculating of the size dependence of g factor and by establishment of the connection with two-dimensional case. The g-factor anisotropy increases with the size of the quantum dot. The analysis of the wave function structure shows that the g factor and its size dependence are mainly controlled by the contribution of the state with J(z)= +/-3/2, where J(z) is the angular momentum projection on the growth direction of the quantum dot.