Spin magnetic moment in half metals.

[Sudhir Regmi]

I read that the stoichiometric half-metallic compound has integer spin moment. For this, n(up)-n(down) should be integer. Since n(up) +n(down) is always integer, either n(up) or n(down) should be integer to make total spin moment integer. I could not understand how the presence of energy gap in one of the spin channel( property of Half Metal) makes the value n(up) or n(down) integer. Where n is the no. Of electrons per unit cell.

 

[BigJDubs]

The presence of an energy gap in one spin channel of the stoichiometric half-metallic compound is what allows the spin moment to be integer. The energy gap effectively isolates the two spin channels, so that the electrons in each channel can be counted separately. Since each electron carries a spin moment of 1/2, the total spin moment can be calculated by summing up the spin moments of the electrons in each channel. If the total number of electrons in each channel is an integer, then the total spin moment will also be an integer.