IGNOU MPHE 27 2026 - Describe the property of band inversion in a topological insulator. He

Question

Describe the property of band inversion in a topological insulator. Hence explain why a topological insulator cannot be transformed into a normal insulator.

19 Jan 2026

Answer :

Word Count : 268

In nanoscale materials, a topological insulator (TI) is characterized by a unique electronic property known as band inversion. In conventional insulators, the conduction band lies above the valence band, separated by an energy gap. However, in a topological insulator, strong spin-orbit coupling causes the conduction and valence bands to invert near certain points in the Brillouin zone, meaning that the conduction band acquires characteristics of the valence band and vice versa. This inversion results from

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