Fermi Definition and 336 Threads

As I know chemical potential of two reacting substances strongly depends on difference in Fermi energy between them. Fermi energy is inversely proportional to the mass of particles. Does that mean that Fermi energy of bare proton will be 2000 time smaller than that of electron? Usually...

How can an electron's momentum be less than the Fermi momentum? Since the Fermi momentum (energy) is measured at absolute zero.

Homework Statement I have to find the Fermi Coupling Constant using my measurement of the muon lifetime. My measurement is 2.1786x10^-6s Homework Equations G_F=\sqrt{\frac{192.pi^{3}}{\tau.m_{\mu}}} The Attempt at a Solution I tried plugging in the numbers that I have and I get...

Hi everyone! I wanted to ask if in your opinion is it right to say that band structure calculations (and hartree fock calculations) could live in a framework of the fermi liquid theory where quasiparticles are one-electron states (which could be or not could be the case)...

can any1 explain what fermi level is simple explanation also how are minority charge carriers formed and i can't understand the energy band diagram of pn junction that how both the fermi levels become equal WHAT IS MEANT BY THAT FERMI LEVEL i read in hyperphysics but i can't understand it...

Relations for an ideal Fermi gas: \frac{P}{k_BT}=\frac{1}{\lambda_D^3}f_{5/2}(\lambda) \frac{1}{\upsilon}=\frac{1}{\lambda_D^3}f_{3/2}(\lambda) But in some book books I find \frac{P}{k_BT}=\frac{g}{\lambda_D^3}f_{5/2}(\lambda)...

Homework Statement Hi all I can't seem to figure out, why semicodunctors do not have Fermi surfaces. At T=0K, there are no electrons in the conduction band, and thus there is no Fermi surface - all OK here. But at T > 0K, there are electrons in the conduction band. Why is it then that it...

Hi there, i've already read some topics in this forum about the fermi-energy/chemical potential. I've also read the article "The chemical potential of an ideal intrinsic semiconductor" from Mark R. A. Shegelski which made the whole thing a little bit more clear to me. but there are some...

In the theory of superconductivity BCS theory is given eigen - problem -\frac{\hbar^2}{2m}(\Delta_{\vec{r}_1}+\Delta_{\vec{r}_2})\psi(\vec{r}_1-\vec{r}_1)=(E+2\frac{\hbar^2k^2_F}{2m})\psi(\vec{r}_1-\vec{r}_1) Why E+2\frac{\hbar^2k^2_F}{2m}? Maybe because is Fermi sphere is centered in...

1. There are many different definitions of the location of the top of the atmosphere – the near edge of outer space. • Until around 1600, it was believed that the Earth’s atmosphere extended throughout space (recall that the Earth was also considered to be the center of the Universe until...

Hello guys, very short question :), why does Fermi level go down with temperature? is there some physical explanation or discussion for this? apart from mathematics (well, some mathematics would be cool if necessary :)) Find attached some cool curve about this ;) Thanks guys :)

please help in this problem what are these basis and what are there there properties.how i can i put there values to solve my problems. ˆB  = ( 1 2  + +)er er  + ( 1 2  − +)e e  + (× + !)er e  + (× − !)e er  . (4.13) where eµ  are co-frame basis satisfying...

Hi People. I was looking at the derivation(s) of Fermi-Dirac Statistics by means of the "most probable distribution" (I know the correct way is to use ensembles, but my point is related to this derivation) and it usually employs Lagrange multipliers and Stirling's approximation on the...

I'm reading Enrico Fermi's "Thermodynamics" book. In page 3 of his book, he says: It is evident from what we have said that the knowledge of the thermodynamical state alone is by no means sufficient for the determination of the dynamical state. What does he mean by dynamical state...

at Fermi lab they create anti-matter or I guess they don’t create it but they synthesize it , where do they keep it so it doesn't react with regular matter and produce light.

Homework Statement We must calculate the Fermi energy of metallic potassium at 0K. We have aleady found the number of atoms per m cubed, we are told that each atom contributes one electron to the free electron gas. Homework Equations Fermi energy = ((hbar^2)/2m)(((3Pi^2)N)/V)^3/2 The...

Homework Statement Show that the fraction of electrons within kT of the fermi level is equal to 3kT/2Ef, if D(E) = E^1/2. Homework Equations f(E) = 1 / ( exp(E-Ef)/kT + 1 ) fermi distribution N = integral from 0 to inf of D(E)f(E)dE = total no. of electrons The Attempt at a...

At 0k, why is fermi level halfway in bandgap?? Fermi Level is defined as the maximum energy an electron posesses at 0k, which appears to be midway in the bandgap. I learned that in the bandgap, there are no available states (i.e. no wavefunctions of electrons) hence, no electrons can possibly...

When we are calculating the fermi energy, we say that each energy level is 2 fold degenerate and the fermions stack up into higher and higher energy level due to the Pauli Exclusion Principle. My question is: The Pauli Exclusion principle only says that we can't put different fermions into the...

Homework Statement I am wondering about something: Calculate the Fermi energy for the neutrons confined to a nucleus with 40 protons and 50 neutrons which roughly forms a sphere of radius 4.6 10^(-15) m. Homework Equations the formula of the fermi Energy is EF=...

I am wondering about something: Calculate the Fermi energy for the neutrons confined to a nucleus with 40 protons and 50 neutrons which roughly forms a sphere of radius 4.6 10^(-15) m. the formula of the fermi Energy is EF= ((h-bar)^2*(3*pi^2*n)^(2/3))/2m m:mass of electron, n = number...

relation of fermi energy in 3D is E=h(cut square)k(square)/2m, if i want a relation of fermi energy in 2D,what should i do?

Hi everyone I need the historical articles that bose and fermi integrals were defined for the first time. Can anyone help me?

Hi, Is this right: Fermi velocity is the velocity of electron-wave in a conductor. Why is it called Fermi velocity, i.e. what is its relation with Fermi energy, etc.. Thanks a lot. Cheers

Hi all, I'm studying on the current transfer at quantum level and I have a point that is not so much clear. While reading the Fermi sphere from the book "Current at the nanoscale", I could not understand the expression: The number of electrons in the conductor, N, is the ratio of the...

Homework Statement What fraction of the 3s-electrons of sodium is found within an energy k_b*T below the Fermi level? (Take room temperature at T= 300k) Fermi level for Na is 3.2 eV Homework Equations F(E) = 1 / {exp((E-E_f)/k_b*T) + 1} The Attempt at a Solution From what I can...

http://www.symmetrymagazine.org/breaking/2009/02/19/most-extreme-gamma-ray-blast-also-probes-quantum-gravity/Fermi%20Observations%20of%20High-Energy%20Gamma-Ray%20Emission%20from%20GRB http://www.nasa.gov/mission_pages/GLAST/news/high_grb.html...

Hi, Ok, so let's say we have a non-degenerate n-type semiconductor such that the Fermi-level/chemical potential is somewhere in the bandgap (probably needs to be low temperature). Typically in a metal you would say that the Fermi velocity is \hbar k_F/m_e. But since the Fermi-energy is below...

Homework Statement (I copy-pasted the question) Consider N non interacting electrons inside a 3D box similar to the one we saw in class, but this time it is not cubical, i.e. Lx = Ly \neq Lz. 1. Calculate the fermi energy as a function of N;Lx;Lz;me... 2. What happens if we take Lz --> 0...

if fermi level is defined for 0K, then how does it vary in a semiconductor with temperature. also, why will the formation of holes affect the position of fermi level(by introducing acceptors). have i misunderstood something? please clear my doubt.

Hi, Im just wondering, why the fermi level rise up with raisng up the temperature when donors are present in Extrinsic semiconductor? thanx

I've been reading an article that refers to the distance of a fermi. What is this in SI units? A google search isn't proving fruitful. Cheers!

I've found the simplest hopping Hamiltonian for fermions (diagonal in momentum space) has a so-called Fermi sea ground state. H = -2 t \sum_k \cos(k) f^+_k f_k (t is some parameter in units of energy). How do I evaluate the expected value of the spin exchange operator S_x \cdot...

Hi everybody, I have the following homework assignment: 1. Derive the expression of density of state D(E) in free electron system. D(E) = \frac{m\sqrt{2m}}{{\hbar}^3\pi^2}V\sqrt{E}, (1) where m and V are electron mass and volume of the system, respectively. 2...

hello to everyone. It is normally said that in semiconductors the Fermi level is half way between the valence and the conduction band. I have the following question on that: what does it mean that the Fermi level is in the band gap? It should mean that the maximum energy of an electron in the...

i know this is a simple question, but i have been looking for a while (maybe 15 min) and i cannot find what is so special about Cu, Ag, and Au? i know there is something special about these 3 metals. something that none of the other metals have. i remember it having to do with fermi velocity /...

In classical statistical mechanics, temperature of a system is the measure of its average kinetic energy. In quantum statistical mechanics, Fermi energy corresponds to last filled level at absolute zero and corresponding temperature is the Fermi temperature. Is the Fermi temperature also take...

[SOLVED] Fermi Dirac- missing something from Ashcroft derivation Homework Statement Deriving Fermi Dirac function following ashcroft all good up to equation 2.43 but then it does the folowing at 2.44 and I can't see how you reach 2.44. Homework Equations as (2.43) f_{i}^{N}= 1-...

Homework Statement (a)If a silicon crystal is doped with 10^15 cm−3 phosphorus atoms, find out the electron concentrations and hole concentrations in the silicon at room temperature. Find out the Fermi level. (b)Repeat at temperature = 0K Homework Equations n*p=ni^2...

[SOLVED] radius of the fermi sphere Homework Statement On page 249 of ISSP, Kittel says that the radius of a free electron Fermi sphere is k_F = \left(3 \pi^2 n \right)^{1/3} where n is the concentration of electrons. I don't know why that is true. EDIT: never mind; they derive that on...

in a Fermi gas, we know that when the temperature is much less than the Fermi energy, it becomes a degenerate gas. does this mean the chemical potential of the system be very large?

I am reading 'Mesoscopic electronics in Solid State Nanostructures', second edition, by Thomas Heinzel. And I find it a bit too difficult from time to time. Especielly on the concept of Fermi level pinning in doped semiconductors. Does anyone know where to find a good explanation for this...

fermi level?? is there any relation ( equation) that give the fermi energy level in terms of Na and Nd the concentration of dopant??

My thoughts "Emergent physics: Fermi point scenario G.E. Volovik" http://arxiv.org/abs/0801.0724 Emergent physics: Fermi point scenario G.E. Volovik What if Volovik is correct that the true TOE is some sort of Fermi point scenario? 1 string theory is dead, and SM particles are not...

I feel dumb that I can't figure this out. I'm sure its something simple that I'm just not seeing, but its really frustrating. Homework Statement How many electrons (in percent of the total number of electrons per mole) lie KbT (ev) below the Fermi energy? Take Ef=5eV and T=300K...

I understand that for a semiconductor p-n junction under zero voltage, the Fermi level is constant throughout the junction because that is the condition for a system in thermodynamic equilibrium. I also understand that p-n junction under applied voltage (forward or reverse) is not a system in...

I don't really understand why the Fermi-Function is often used to describe superconductors. According to the BCS theory Cooper pairs should be Bosons with Spin 0. Wouldn't it make more sense to use the Bose-Einstein-Function? Thanks Tanja

Suppose we have particles of kind B, that consist of two fermions of kind F. Now the particles B satisfy the Bose statistics. But what precisely does this mean? If we have four F particles, the system is described by a wave function \psi(x_1,x_2,x_3,x_4) Suppose the particles 1 and 2...

Hello all! My professor talked about the quasi fermi levels in my Photonics class. While he did make a good effort, I still am not able to understand the concept. I do plan on going to him on Tuesday to get a clearer idea. But I was wondering if any of you folks could give a general...

Homework Statement The probability of a person quantum mechanically tunnelling through a wall Homework Equations The Attempt at a Solution I'm not too sure how to approach this problem, I calculated the de Broglie wavelength of the person (mass = 60kg, velocity = 30 m/s; These values are...