Difference of the spin Hall effect in intrinsic and extrinsic semiconductors?

[JanSpintronics]

Hello there,

I don't really get the difference between the extrinsic or intrinsic spin hall effect or contribution. As i understand, in extrinsic you have spin scattering by impurities, so its the spin orbit interaction of the spin with its orbit, and this orbit is influenced by an impurity.

In the intrinsic, they say it is also due to spin orbit interaction caused by the bandstructure…but in my opinion its the same as the extrinsic. the bandstructure is also made by impurities. It is meant so, the electron get a transversal component cause of scattering with the "main" atoms?

I also read, intrinsic Spin hall effect is happened DURING sacttering events, so it does not happened in scattering events. But Spin orbit interaction IS scattering (for me all spin orbit interactions do lead to a change in direction). So is that kind of spin orbit interaction in extrinsic and intrinsic different, and if s, where is the difference?

I also read something About the berry face, about and periodic parameter who gives rise to the intrinsic. Should i understand that like an electron which is coming back to its position, so its periodic and then its get , however, a transversal component?

Hope someone can help me,

 

[eljose79]

thanksHello there,

I can definitely understand why the difference between the extrinsic and intrinsic spin hall effect may be confusing. Let me try to clarify it for you.

First, let's start with the extrinsic spin hall effect. As you mentioned, this is caused by spin scattering by impurities. This means that the spin of an electron is affected by the presence of impurities in the material. These impurities can cause the electron's spin to change direction, resulting in a transverse spin current. So, in this case, the spin orbit interaction is due to the impurities in the material.

On the other hand, the intrinsic spin hall effect is caused by the spin orbit interaction within the bandstructure of the material itself. This means that the bandstructure of the material has a built-in spin orbit coupling, which can cause the spin of an electron to change direction and result in a transverse spin current. This is not influenced by impurities, but rather is an inherent property of the material's bandstructure.

Now, you may be wondering, what is the difference between spin orbit interactions in the extrinsic and intrinsic cases? The main difference is that in the extrinsic case, the spin orbit interaction is caused by impurities, while in the intrinsic case, it is caused by the bandstructure of the material itself. In both cases, the spin of the electron is affected, but the underlying cause is different.

Regarding your question about the Berry phase and periodic parameters, these are related to the intrinsic spin hall effect. The Berry phase is a geometric phase that describes the change in a wavefunction as it moves along a closed path in space. This is relevant to the spin hall effect because the spin of an electron can be affected by its path in the material's bandstructure. The periodic parameters refer to the periodicity of the material's bandstructure, which can also affect the spin of an electron and result in a transverse spin current.

I hope this helps clarify the difference between the extrinsic and intrinsic spin hall effect. Let me know if you have any other questions. Happy to help!