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View Full Version : relaxation time = displacement lifetime of fermi sphere?


neu
Apr20-07, 04:31 PM
1. The problem statement, all variables and given/known data

I just want to clear this up, im a little confused:

when an electric field is applied there is a force on the electron K-states thus displacing the fermi surface/sphere

Is the relaxation time ( \tau)= lifetime of fermi sphere displacement

or is lifetime of displacement= reciprocal relaxation time

both are labebel as \tau in my notes and related as below but how can they be the same?


2. Relevant equations

\sigma = \frac{n e^2 \tau}{m} electrical conductivity

\rho = \frac{1}{\sigma}=\frac{m}{n e^2 \tau} electrical resistivity

solas99
Aug15-11, 09:53 AM
Given the following data on copper, how do i calculate the resistivity?

Relaxation time: 2.50e10-14s
Density: 8940Kgm-3
molar mass: 63.5g

is there an equation for it.