Topological insulator structure

A topological insulator structure, comprising:

• an insulating substrate;
• and
• a magnetically doped topological insulator quantum well film located on the insulating substrate;
• wherein a material of the magnetically doped topological insulator quantum well film is represented by a chemical formula of Cry(BixSb1-x)2-yTe3, wherein 0<x<1, 0<y<2, and values of x and y satisfies that an amount of a hole type charge carriers introduced by a doping with Cr is substantially equal to an amount of an electron type charge carriers introduced by a doping with Bi;
• and the magnetically doped topological insulator quantum well film is in a range of 3 QL thickness to 5 QL thickness.