Electron holes and current

[Bohandas]

As many of you probably know, the direction of current depicted on most diagrams is actually the opposite of the direction that the electrons actually move; a holdover from a time before electricity was completely understood.

What I want to know is if one could accurately think of the current as electron hole quasiparticles traveling in the direction depicted on the diagram (opposite the direction of electron flow) or if the convention of depicting the current moving from plus to minus was a indeed a complete and total screwup.

(Also, secondary question while on the topic of quasiparticles, coukd it be possible to make the absence of an expected oxygen atom move around in a particle-like manner the way the absence of an electron can? And if it is, would this quasiparticle have properties similar to the pholgiston postulated by the obsolete theories of combustion which preceeded the discovery of redox chemistry?)

[gomipile]

If all you care about is the frictionless planes and spherical cows that allow us to usefully predict how a circuit will behave in general, then yes.

However, if you're looking closely enough to measure momentum with sufficient precision to discern the momentum of the electrons in a wire, then no.

For instance, if you look at an electronic device that depends on producing and manipulating electron beams, the "hole" picture doesn't work so well. It works fine as a useful approximation within a wire, where there is plenty of positive charge balancing out the electrons. But in a vacuum with just electrons sailing through it, not so much.

[halfeye]

If all you care about is the frictionless planes and spherical cows that allow us to usefully predict how a circuit will behave in general, then yes.

However, if you're looking closely enough to measure momentum with sufficient precision to discern the momentum of the electrons in a wire, then no.

For instance, if you look at an electronic device that depends on producing and manipulating electron beams, the "hole" picture doesn't work so well. It works fine as a useful approximation within a wire, where there is plenty of positive charge balancing out the electrons. But in a vacuum with just electrons sailing through it, not so much.

So it's good for transistors, not so good for the vacuum tubes they mostly replaced?

[gomipile]

So it's good for transistors, not so good for the vacuum tubes they mostly replaced?

As an analogy, yes.

[khadgar567]

?...
that's all i want to say.

[BannedInSchool]

Huh, didn't know "electron hole" was the name of a real thing before. I just knew it as an EE joke.

[khadgar567]

Huh, didn't know "electron hole" was the name of a real thing before. I just knew it as an EE joke.

you can watch EE's last role on youtube were he plays Lancelot in high school in stream account.

[wumpus]

There's some really strange work on this going on now. I'm not sure how much this is the universities PR department hyping things well past their own knowledge, or quantum physics being its usual weird self, but presumably 'electron holes' can be convinced to be more than the absence of electrons:

https://physics.illinois.edu/news/article/24114

[Xyril]

What I want to know is if one could accurately think of the current as electron hole quasiparticles traveling in the direction depicted on the diagram (opposite the direction of electron flow) or if the convention of depicting the current moving from plus to minus was a indeed a complete and total screwup.

I thought you were making a tongue-in-cheek joke until I followed your link and realized the wiki article actually omits this fact: A substantial chunk of the field of semi-conductor modelling in EE is based on the idea of treating electron holes as a quasi-particle. Essentially, under certain conditions a semi-conductor is a good conductor because it has electrons that can be displaced with minimal energy, and under other conditions it is a good conductor because it can easily accept free electrons, and treating the latter case as having loose, positively charged "hole" carriers can be a useful way to model behavior. So I wouldn't call it a complete and total screwup because it remains a useful way to look at the world. As for whether it's accurate, I suppose it depends on your definition of accurate. Everything we know about science is essentially a construct to understand and model the truth to the best of our ability. The positive hole carrier hasn't entirely lost its usefulness as a way to think analytically about electricity, but it isn't consistent with how we now think about the composition of matter. However, it's also possible--even likely--that as we understand the universe more, we'll find another way of looking at things that make both of these models look inaccurate. It's already happened to some extent--the way we think of the dual nature of particles and waves now means that how we view electrons might seem pretty bizarre to guys who simply thought of the as these newly discovered charge-carrying particles.

[wumpus]

I thought you were making a tongue-in-cheek joke until I followed your link and realized the wiki article actually omits this fact: A substantial chunk of the field of semi-conductor modelling in EE is based on the idea of treating electron holes as a quasi-particle. ...

I should like to point out that schematics are invariably drawn and analyzed assuming that electric power travels from positive terminal to negative terminal. Working with "holes" almost certainly is wildly more natural to any electrical engineer (silicon crystal physicists might have some issues with the idea).

See https://xkcd.com/567/ for an example.