Fermi energies and Fermi temperatures for some metals. The integer that follows
ID: 474914 • Letter: F
Question
Fermi energies and Fermi temperatures for some metals. The integer that follows the clement symbol is the number of conduction electrons contributed by each atom. The typical separation (V/N)^1/3 is given in units of 10^-10 meter (1 angstrom). The separations are those at 20 degree C [except for Na (25 degree C) and K (18 degree C)]. In almost all cases. the experimental Fermi temperature comes from measurements at 4 K or less. Sources: Encyclopedia of the Chemical Elements, edited by Clifford A. Hampel (Reinhold, New York, 1968) and AIP Handbook, 3rd edn, edited by D. E. Gray (McGraw-Hill. New York, 1972). What do you notice about the experimental Fermi temperatures as compared to the theoretical Fermi temperatures in Table 9.1? What might explain this observation?Explanation / Answer
the fermi temperature TF is the temperature associated with the Fermi energy by solving
EF = kTF
for TF , where m is the particle mass and k is boltzman's constant giving
TF = EF/k
from the table 9.1,
the point of Fermi surface is that this is where all of the low lying excitations of the system live . the fermi energy is so much larger that from room temperature that for room tempertature experiments, all of the termodynamics is dominated by excitations right at the fermi surface and thus knowing its structure is very important.
A more advanced reason for the importance of the fermis surface is that by knowing its structure. from table 9.1 understand that the instabilities of a metal , for example for sufficiently low temperature , a normal metal settling into a charge wave state.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.