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the number of electron for resistivity calculations 
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Joined: Thu Dec 20, 2018 8:58 am
Posts: 2
University: Peking University
Post the number of electron for resistivity calculations
Hi,

I'm using EPW to calculate the resistivity of metals. Following the tutorial of School 2018, I've reproduced the resistivity of lead.

But there is a question about the number of electrons included in the Ziman's formula. As the tutorial said, "n is the number of electron per unit volume and n(ω,T) is the Bose-Einstein distribution. Usually, this means the number of electrons that contribute to the mobility and so it is typically 8(full shell) but not always.".

So for example, the number of electron per unit cell of sodium is one, isn't it? If so, the calculated resistivity (multiplied by eight) of sodium is about two times larger than the experimental value.

I'm so confused, could anyone tell me how to deal with that?

Thanks a lot

Best regards,

Xiaowei
ICQM, PKU, Beijing


Thu Jun 27, 2019 1:44 pm
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Joined: Wed Jan 13, 2016 7:25 pm
Posts: 575
University: Oxford
Post Re: the number of electron for resistivity calculations
Hello Xiaowei,

From Ziman, it should be "the number of electrons contributing to the mobility".

This is indeed vague. I originally interpreted this as the number of electrons in the last shell.

However, a better way could be to count the number of electrons around a small energy windows around the Fermi level (does not have to be an integer number).

More easily you could count the number of bands crossing the Fermi level (integer number).

Hope this helps,
Samuel

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Dr. Samuel Poncé
Department of Materials
University of Oxford
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Oxford OX1 3PH, UK


Tue Jul 09, 2019 1:54 pm
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Joined: Thu Dec 20, 2018 8:58 am
Posts: 2
University: Peking University
Post Re: the number of electron for resistivity calculations
Hi Samuel,

It is clear now. Thanks for your reply!

Best,

Xiaowei


Thu Jul 11, 2019 3:54 am
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