I get that in a single particle of a metal, Fermi energy is defined at T = 0 as the maximum energy that electrons can reach. I get that, but my book defines this concept called Fermi Temperature. Is Fermi Temperature the temperature where electrons can reach the next empty energy band in support of heat energy, not by the direct influence of photons? Also, I would like to know if reaching Fermi temperature means the electrons will act upon Fermi-Dirac distribution rule(which I think means at that temperature electrons they would act like a regular gas, which otherwise they wouldn't.) (I looked up 'Fermi Energy' in wiki, and couldn't find the proper explanation for Fermi Temperature.) Thank you in advance.