Occupation-number broadening schemes: Choice of "temperature"

Band-structure calculations frequently use an occupation-number broadening method to approximate integrals involving the electronic density of states. The underlying assumptions of these techniques are frequently unstated and can lead to erroneous results. In particular, a sampling of recent papers shows that very few authors check the behavior of the integrals as a functi on of the broadening parameter ("temperature"). The correct temperature for one calculation may not be correct for another calculation in the same sys tem. This paper uses a tight-binding calculation of the elastic constants i n Niobium as an example of what can happen when the broadening parameter is not carefully applied.