High-field Hall Effect

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  • Thread starter Rzbs
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Summary:

Hall effect in the high-field limit
Could any one please explain the differnce between these two picture of Ashcroft & Mermin solid state physics book:
Screenshot_20201106-163501.png
Screenshot_20201106-163413.png

Why in these two pictures the + and - signs don't compatible with each other?! I think in the pic12-11 the signs don't draw correctly. It must be vice versa I mean + signs in left and - signs in right?!
 

Answers and Replies

  • #2
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Its OK. The B field is reversed which is why charges may appear off.
 
  • #3
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Its OK. The B field is reversed which is why charges may appear off.
Thanks. So you say in the second picture the H field is along -z direction?

but It seems in two pictures the H fields are along +z direction and Js are along +x direction, but in the first picture Ey is along -y and in the next picture it's along +y! Why? What is my mistake?
 
  • #4
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Thanks. So you say in the second picture the H field is along -z direction?

but It seems in two pictures the H fields are along +z direction and Js are along +x direction, but in the first picture Ey is along -y and in the next picture it's along +y! Why? What is my mistake?
Second diagram had "B" next to a circle with a dot in it. If it was the other direction then it would be a circle with an x in it. Did you note that the two diagrams are about different things? They are not meant to be identical.
 
  • #5
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Second diagram had "B" next to a circle with a dot in it. If it was the other direction then it would be a circle with an x in it. Did you note that the two diagrams are about different things? They are not meant to be identical.
I agree that the drawings are not well thought out but I didn't see the whole paper. Drawings should improve the quality of the paper, not obfuscate. Hall effect is a basic part of physics, BUT this paper was about Hall Effect at very high field strength and how it was different from ordinary Hall Effect normally encountered. Like anything at extremes (metallic Hydrogen at extreme Jupiter-like pressure) there are surprise changes in how materials behave.
 
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  • #6
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Second diagram had "B" next to a circle with a dot in it. If it was the other direction then it would be a circle with an x in it.
I know the meaning of a circle with a dot or with an x. So in second diagram +z is outward of the page.

Did you note that the two diagrams are about different things? They are not meant to be identical
The two diagrams are in Ashcroft and Mermin solid state physics book in different chapters. The second one tried to explain the unusal behavior of the first one like postive hall coefficient and behaviour of magnetoresistance.
 
  • #7
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I agree that the drawings are not well thought out but I didn't see the whole paper. Drawings should improve the quality of the paper, not obfuscate. Hall effect is a basic part of physics, BUT this paper was about Hall Effect at very high field strength and how it was different from ordinary Hall Effect normally encountered. Like anything at extremes (metallic Hydrogen at extreme Jupiter-like pressure) there are surprise changes in how materials behave.
The two diagrams are about one thing and I think should be like each other. Maybe in the second one the charge careers are positive (I'm not sure because the book don't say anything about this).
 
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