Positrons and Holes


by Swapnil
Tags: holes, positrons
Swapnil
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Nov17-06, 05:35 PM
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I am studying the concept of holes in my device physics class. They say that holes a hole is just an absence of an electron. Yet we do all kinds of stuff with holes as though it was a real physical particle.

So here's is the question. Are holes and positrons the same thing or possibly the same thing? If they are, then it would give me a reason to believe that holes are something more than just something we invented for convenience.
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Hurkyl
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Nov17-06, 05:47 PM
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holes are something more than just something we invented for convenience.
But you didn't "invent" it; the hole is there whether you acknowledge it or not. So what if the hole shares many qualities with "real" particles? That just means those qualities aren't the exclusive property of real particles.
mathman
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Nov17-06, 06:14 PM
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Holes and positrons are quite different. Holes are absences of electrons, with the excess + charge from atomic nuclei. Positrons, as you know, are anti-electrons, which would quickly be annihilated by contact with electrons.

ZapperZ
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Nov17-06, 07:06 PM
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Positrons and Holes


Quote Quote by mathman
Holes and positrons are quite different. Holes are absences of electrons, with the excess + charge from atomic nuclei. Positrons, as you know, are anti-electrons, which would quickly be annihilated by contact with electrons.
However, the mathematics are the same.

The ground state of a fermionic system is equivalent to the vacuum state. The creation of an electron and a hole out of the ground state has the identical description of the electron-positron pair creation. The recombination of electron with a hole can, in fact, generate a photon the same way that electron-positron anhilation can.

The major difference between the two analogies is that a hole can have a different "effective mass" than an electron, because it can "live" in an entirely different electronic environment.

Regardless of that, the consideration of a hole as if it is any ordinary particle is as valid as any other description that we have within condensed matter/solid state physics.

Zz.
lightarrow
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Nov18-06, 02:26 AM
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Quote Quote by Swapnil
I am studying the concept of holes in my device physics class. They say that holes a hole is just an absence of an electron. Yet we do all kinds of stuff with holes as though it was a real physical particle.

So here's is the question. Are holes and positrons the same thing or possibly the same thing? If they are, then it would give me a reason to believe that holes are something more than just something we invented for convenience.
Consider that a hole behaves differently from an electron, in a solid, e.g., a semiconductor; for this reason it can be considered as "a particle", but different from an electron; this should be enough for you, since, even for a real physical particle, you study its properties and its behaviour, as Hurkyl said.


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