QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: GJK on May 14, 2014, 10:30

Title: Fermi energy-reg
Post by: GJK on May 14, 2014, 10:30

Hi,

The Fermi energy (EF) of a system of non-interacting fermions is the increase in the ground state energy when exactly one particle is added to the system, minus the potential energy of that particle.
It can also be interpreted as the maximum kinetic energy of an individual fermion in this ground state.
The internal chemical potential at zero temperature is equal to the Fermi energy.
These are the definitions obtained from http://en.wikipedia.org/wiki/Fermi_energy
 In my previous mail It is answered to calculate the chemical potential which gives Fermi energy.If my system is Graphene nanoribbon should I do chemical potential analysis for Fermi energy calculation at room temp (for my system 300 K) or at 0K

Thanks in advance

Title: Re: Fermi energy-reg
Post by: Anders Blom on May 14, 2014, 12:51

All calculations of this kind are formally carried out at 0 K in DFT. There is a bit of thermal broadening of the Fermi distribution for numerical reasons, to stabilize convergence, but the proper lattice temperature does not enter the equations.