Questions tagged [fermi-energy]
183 questions
38
votes
5 answers
What's the difference between Fermi Energy and Fermi Level?
I'm a bit confused about the difference between these two concepts. According to Wikipedia the Fermi energy and Fermi level are closely related concepts. From my understanding, the Fermi energy is the highest occupied energy level of a system in…
Eddy
- 537
12
votes
2 answers
Fermi level and conductivity
Can someone in a simple way explain me what the Fermi level is and what does it have to do with conductivity. My teacher said that Cu conducts electric current better than Al because of something in relation to Fermi level, I didn't get him very…
A6SE
- 255
11
votes
2 answers
Semiconductors/insulators: Why is the fermi energy between the valence and conduction band?
Ive asking myself a question on the fermi-energy.
The fermi-energy is defined as the maximum energy which an electron, following the Pauli-rule, can have at T=0.
In semiconductors and insulators the valence band is full while the conduction band is…
S. Den
- 141
11
votes
2 answers
What does the Fermi Energy really signify in a Semiconductor?
In understanding the behavior of semiconductors, I'm coming across a description of the Fermi Energy here and at Wikipedia's page (Fermi Energy, Fermi Level). If I understand correctly, the Fermi Level refers to the energy state at which there's a…
Perrako
- 213
10
votes
1 answer
Tight-binding vs. nearly free electron (NFE) model predictions
I came across the following problem:
Suppose that a certain material consists of $N$ atoms that are ordered in a 2D lattice with a lattice constant $a$, and that each atom donates two conduction electrons at $s$-level. Determine whether the…
grjj3
- 705
9
votes
3 answers
What is the significance of Fermi temperature?
The Fermi temperature of a solid is related to Fermi energy by relation
$$
{ E }_{ F } ={ k }_{ B }\times{ T }_{ F }
$$
where $ { k }_{ B } $ is Boltzmann constant.
But what is the significance of Fermi temperature?
KrnTneJa
- 101
7
votes
0 answers
How do I use de Haas-van Alphen oscillations to find the Fermi surface?
Background: Ashcroft and Mermin provide a discussion in Chapter 14 describing de Haas-van Alphen oscillations and their use in measuring the Fermi surface of a material. In doing so, they present the expression $\Delta \biggl( \frac{1}{H} \biggr) =…
Relativisticcucumber
- 1,987
6
votes
1 answer
Meaning of Fermi energy in semiconductor
We know from the band theory that in a semiconductor (of course for all metals, insulator) all energy states are not allowed. In a semiconductor there is a valence band and a conduction band, and in between energy states of them i.e energy levels…
radiationgalaxy
- 236
6
votes
1 answer
The concept of Fermi level
I have read and used the concept of Fermi level previously and this is simply an attempt on my side to better my understanding of it by asking myself various questions. I understand that the fermi distribution is defined as…
Ghosal_C
- 1,418
6
votes
1 answer
How does fermion degeneracy affect elastic scattering in astrophysical compact objects?
As I currently understand it, absorption processes or inelastic scattering involving fermions in a degenerate gas are strongly inhibited, because to change the fermion energy (or create a new fermion) requires it to be placed in a vacant energy…
ProfRob
- 141,325
6
votes
1 answer
Why do insulators have "just enough" electrons to fill the valence band
This is the classic picture of the band structure for an insulator (or semi-conductor):
The common explanation as to why this doesn't conduct is that the electrons fill the valence band perfectly full so that it is a traffic jam, and that there is…
Kevin Kostlan
- 6,875
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5
votes
1 answer
Landau tubes and Fermi sphere
A question regarding Landau tubes:
I cannot understand why pictures of the Landau tubes are in k space as the Fermi sphere, especially considering the fact that $k_y$ ceases to be a good quantum number to describe an electron in presence of a…
5
votes
1 answer
Liquid mercury, relativistic effects and Fermi velocity
Reading this news article and some related references, I learned that mercury’s liquidity is due to relativistic effects in Hg, where "the electron approaches about 58% of the speed of light." I do not see how this can be reconciled with the…
Andrea Alciato
- 1,153
5
votes
2 answers
What is the importance of the Fermi energy $E_F$ or the chem. potential $\mu$ for topological superconductors?
A lot of effort is put into shifting the Fermi energy of a topological insulator to exactly zero which then provides some advantages when this TI is coupled with a superconductor.
I don't understand why this is important or what advantages this…
Mike
- 51
5
votes
1 answer
Fermi level with Landau levels
So my question is regarding where the Fermi energy is when you have 2D electron gas in an applied magnetic field. My book explains that, using the Landau gauge, you find that the 2D density of states (normally the constant $g_{2D} = m/\pi \hbar^2$)…
user22862