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Cheers.

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- Thread starter joel.martens
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- #1

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Cheers.

- #2

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Effective mass of holes and electrons in semiconductors is closely related to mobility. See

http://en.wikipedia.org/wiki/Effective_mass_(solid-state_physics [Broken])

http://en.wikipedia.org/wiki/Effective_mass_(solid-state_physics [Broken])

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E = hbar^2 k^2 / 2m

where m is the mass of free electron.

Now, in a crystalline solid, where electronic band diagram applies, any band (near a symmetry point) can be represented as parabolic in k space, with its own curvature, i.e.:

E = hbar^2 k^2 / 2m*

where m* is the 'renormalized' mass of an particle in band (electron or a hole).

What is puzzling to me is why in for example semiconductors the effective mass is lower than the free electron mass? If I apply an external electric field, these electrons will reach steady state velocity larger than the free ones... what is physically happening that electron acts as if its inertia is lowered?

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