Resistance and magnetic field effects for p-doped Ge

[MementoMori96]

Hi, we have done an experiment where we have to measure the resistance of a sample of Ge doping-p and how it changes due to a magnetic field perpendicular to the sample with a costant current.
We have found that R(B) has a quadratic trend (we have fit the dates with y = a[1+b*B^2] with a and b free parameters) . Is there a theory that can explain this ?

Thanks :)

 

[Dr Transport]

Hall effect...

 

[MementoMori96]

Yes but how? I’m not able to find the fit theorically

 

[Dr Transport]

The current in a material is affected via the magnetic field and can be equated to a resistance... it isn't an easy calculation but is doable.

 

[MementoMori96]

Thanks ! Have you any books or web pages in which i can deepen this topic?

 

[Dr Transport]

Look for a book on the Hall effect or on a text about Boltzmann transport theory

 

[MementoMori96]

I’m looking at http://physics.gu.se/~tfkhj/161213.pdf , is it correct? It is not so easy but at first glance it seems that the final result is not a simple function, isn’t it?

 

[Dr Transport]

No, not a simple function, exactly what I said previously. Yes, you are on the right track, magneto-resistance is what you measured and are calculating.

 

[MementoMori96]

Hi, this doubt is born because my professor has found this quadratic trend in this way (see the image)

But if we fit the dates with the function that i have written before we will not find the mobility that we have measure with the usual method but mobility/2. Why?

 

[MementoMori96]

Hi, this doubt is born because my professor has found this quadratic trend in this way (see the image)

But if we fit the dates with the function that i have written before we will not find the mobility that we have measure with the usual method but mobility/2. Why?

Anyone ?