Spin – Orbit interaction:

Objectives:

The spin-orbit interaction (also called spin-orbit effect or spin-orbit coupling) refers to interactions of a particle's spin with its motion. This interaction causes shifts in an electron's atomic energy levels due to electromagnetic interaction between the electron spin and the nucleus magnetic field. A similar effect, due to the relationship between angular momentum and the strong nuclear force occurs for protons and neutrons moving inside the nucleus. In the field of spintronics, one of the major mechanisms that determine the spin relaxation time is the spin-orbit interaction. Hence, it is important to understand the spin-orbit interaction in details, as it forms the basis of many spin-based devices.

Therefore, the following two lectures are framed

1. 1. to describe the spin orbit interaction?
   
2. 2. to derive spin-orbit interaction Hamiltonian, and
   3.
3. to discuss Spin-orbit interaction in a solid using
   
   • • Rashba interaction and
     
   • • Dresslhaus interaction

(1) What is spin-orbit interaction?

The self-rotation of a charged particle about its own axis will give rise to a magnetic moment. The American physicist Kronig ttook this concept and used relativistic mechanics to derive the interaction between the magnetic moment and the orbital angular momentum of an electron in an atom.

Figure 4.1: Schematic drawing of an electron orbiting around the nucleus.