Sample interview questions: Can you explain the concept of excitons and their significance in solid-state physics?
Sample answer:
Excitons
In solid-state physics, excitons are elementary quasiparticles that describe the bounded state of an electron and a hole. They are formed when an electron is excited from the valence band to the conduction band, leaving behind a positively charged hole. The electron and hole are attracted to each other through the Coulomb interaction, forming a bound state analogous to a hydrogen atom.
Types of Excitons
- Frenkel excitons: The electron and hole are localized on the same lattice site. They are typically found in ionic crystals and organic materials.
- Wannier-Mott excitons: The electron and hole are separated by a significant distance, typically on the order of the lattice constant. They are typically found in semiconductors and insulators.
Significance in Solid-State Physics
Excitons play a crucial role in various physical phenomena:
- Optical properties: Excitons can be created and annihilated by absorbing or emitting photons. Their energy levels determine… Read full answer
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