Electron Effective Mass and Effective Mass Theory in Semiconductors

[mendes]

I would like to ask about the reason why the electron "effective mass" was introduced in semiconductors. What is its' usefulness ?

And also about the so-called "effective mass theory" used to calculate energies for the shallow defects in semiconducors. What are mean pecularities and approximations of this theory and why we can't use it to calculate deep defects.

Thanks.

 

[ZapperZ]

I would like to ask about the reason why the electron "effective mass" was introduced in semiconductors. What is its' usefulness ?

Er.. there are many properties that depends on the effective mass. The mobility is one example. So that's one reason why such a concept was introduced.

Another reason is that, within the Fermi Liquid Theory, we can lump all the many-body interactions into this "renormalized" mass (effective mass), creating a "quasiparticle", rather than a bare electron. This allows us to go from a many-body problem (difficult), to many one-body problem (easier).

Zz.

 

[asheg]

Simply because you can behave electrons in semiconductors like in electrons in vacuum with effective mass.

 

[fk08]

in simple metals, the effective mass can be related to the orbital overlap. strongly overlapping orbitals give states with free electron like character, whereas a reduced overlap increases the effective mass..