The Fermi level is only in the middle of the band gap if A) the system is at zero temperature or B) if the electron and hole effective mass are the same. This is such a common question here that I have even memorized a reference: Robert Pierret's Semiconductor Device Fundamentals section 2.5 in general and 2.5.6 in specific.

The Fermi level is a function of temperature (see above reference), so it is almost never put at zero energy on band structure plots.

Out of curiosity, why do you think that the Fermi level needs to be in the middle of the gap? I'm really curious where this misconception comes from. Do bad teachers tell people this? Do people just assume it?

The Fermi level is only in the middle of the band gap if A) the system is at zero temperature or B) if the electron and hole effective mass are the same. This is such a common question here that I have even memorized a reference: Robert Pierret's Semiconductor Device Fundamentals section 2.5 in general and 2.5.6 in specific.

The Fermi level is a function of temperature (see above reference), so it is almost never put at zero energy on band structure plots.

Out of curiosity, why do you think that the Fermi level needs to be in the middle of the gap? I'm really curious where this misconception comes from. Do bad teachers tell people this? Do people just assume it? Confusion between Fermi level and Fermi energy?