Solid-state physics studies how macroscopic properties of solids (mechanical, electrical, optical, etc.) result from their microscopic structure. It usually deals with the scale where quantum properties of the particles are substantial.
3
votes
1answer
99 views
Change of basis in non-linear Schrodinger equation
At the mean-field level, the dynamics of a polariton condensate can be described by a type of nonlinear Schrodinger equation (Gross-Pitaevskii-type), for a classical (complex-number) wavefunction ...
6
votes
2answers
139 views
+50
Ferromagnetism with mobile spins
How can electron spins in Iron at room temperature have ferromagnetic order even though they are travelling at very high speeds?
One could argue that spin and motion are completely uncorrelated and ...
2
votes
1answer
23 views
Origin of interaction in inelastic neutron scatting
In solid state physics, inelastic neutron scattering is a commonly-used experimental technique for probing the energy spectrum of phonon and magnon excitations. This technique relies on the ...
2
votes
1answer
57 views
Estimate the difference between two sets of atoms
I've been working on amorphous structures derived from a crystalline one (using MD) containing $N$ atoms. I want to prove that these structures are different and to quantify their "differentness". One ...
2
votes
1answer
82 views
Liquid benzene magnetic susceptibility
In a solid state physics problem, I'm asked to make a rough estimate of the contribution to the diamagnetic susceptibility of the outer electron of each carbon atom. The wavefunction of these ...
0
votes
1answer
141 views
Why do the drift and diffusion components cancel for each type of carrier if EHP generation plays such big role in p-n-junctions?
I have always argued to myself that drift and diffusion components of the current though a p-n-junction cancel for each type of carrier because any electron diffusing from n into p will sooner or ...
1
vote
1answer
54 views
Distinguish electron-like and hole-like orbits in reciprocal space, with reference to the Brillouin Zones
So I have a solid state and thermodynamic exam next week and I've been going through some of the previous exams from years gone by to prepare. I came across this question "Distinguish electron-like ...
3
votes
1answer
37 views
Dopant concentration and changes in band gap energy
Thanks to this lovely website, I was able to pop out reasonable values for my band gap energies from a translucent material. As expected, I found a decrease in band gap energy due to my treatments.
...
3
votes
0answers
54 views
What is the difference between spin glass and spin liquid?
What is the difference between spin glass and spin liquid?
Do they both originate from frustration?
1
vote
1answer
75 views
How creation of point defects in semiconductors is affected by strain?
When the effect of the strain on solids is discussed, normally the explanation is the following: increasing stress, first point defects created, then dislocations, then plastic deformation starts, ...
-4
votes
3answers
172 views
There must be free positive charges, moving oppositely to electrons for the wire with current to stay neutral
All popular expositions (e.g. these ones) of relativistic electromagnetism claim univocally that electrons in motion become more dense due to the speed. They teach that Lorentz contraction of charges ...
1
vote
2answers
181 views
Thomas-Fermi approximation and the dielectric function (+ small bit on graphene)
1) With the dielectric function, which is a function of wavenumber and frequency,how is it possible to take the limit of either to zero without changing the other one? I thought that frequency and ...
2
votes
0answers
37 views
What are the rainbow and ladder approximations in a solid state physics context?
All references I find talk about quarks and gluons, where I have only very limited knowledge about.
From it's name (rainbow) I guess it applies to fermions coupled to bosons and we're interested in ...
1
vote
1answer
34 views
If my lattice has an atomic basis, do I also find the reciprocals of the basis vectors to get the reciprocal crystal structure?
That is what my crystal structure looks like. The blue atoms sit on every lattice point (basis vector of $\{0,0\}$) and the red atoms have basis vector of $\left\{{2\over3},{1\over3}\right\}$. The ...
2
votes
1answer
64 views
Are electronic wavefunctions in band gap insulators localized? is a single-particle picture sufficient in this case?
I am having trouble understanding the physics of band gap insulators.
Usually in undergrad solid state physics one looks at non-interacting electrons in a periodic potential, with no disorder.
Then, ...
2
votes
0answers
33 views
Is this 2D structure triclinic?
The only rotation axis obvious to me is rotation by 360 degrees, the identity. Vertical mirror planes I've been dicing and cutting it through several planes and I still see none. Yet, the structure ...
2
votes
3answers
95 views
What is the difference between lattice vectors and basis vectors?
Google has not been very useful in this regard. It seems no one has clearly defined terms and Kittel has too little on this.
1
vote
1answer
39 views
What would be the basis vectors for this 2D crystal structure?
In the above image, I have a 2D crystal structure. The lattice vectors are described by:
a = {-1/2, -Sqrt[3]/2};
b = {1, 0};
and the location of atoms A and B ...
7
votes
1answer
350 views
Resistance between two points in an infinite metal sphere/cube
Let's imagine that we have a tridimensional metal object of infinite size, and decide to calculate the resistance between two arbitrary points. How would we go about doing this?
I have thought of two ...
1
vote
1answer
43 views
I can't figure out crystal planes with negative intercepts
As seen above, I don't follow how you figure out those planes. It seems they're not using the origin labeled. I'm not really sure I understand spatially what's going on in the left figure so let's ...
0
votes
2answers
50 views
How does a force on electrons produce a force on a metal plate
In a paper from Cadwell Magnetic damping: Analysis of an eddy current brake using an airtrack about eddy current brakes the author explains the effect qualitatively as follows:
When a ...
2
votes
1answer
31 views
Electric current streamlines in induction cooking vessel
I am looking for a plot of the typical streamlines of the electric induced currents ("eddy currents") in a induction cooking vessel.
How can one theoretically predict the streamlines? How is it ...
6
votes
1answer
328 views
Number density of LO and LA phonons as a function of temperature?
I'd like to know the how the number density of longitudinal optical (LO) and longitudinal acoustic (LA) phonons varies as a function of temperature of the material. Is there a simple expression for ...
12
votes
3answers
561 views
Shine a light into a superconductor
A type-I superconductor can expel almost all magnetic flux (below some critical value $H_c$) from its interior when superconducting. Light as we know is an electromagnetic wave. So what would happen ...
1
vote
1answer
92 views
What is a $p_x + i p_y$ superconductor? Relation to topological superconductors
I often read about s-wave and p-wave superconductors. In particular a $p_x + i p_y$
superconductor - often mentioned in combination with topological superconductors.
I understand that the overall ...
0
votes
0answers
23 views
What are some applications of crystal fabrication? [closed]
I have heard of some applications here or there in certain papers, but I am looking for a broader scope of examples.
1
vote
1answer
48 views
What is the reasoning behind hole carriers being able to carry heat?
In the Peltier effect, we consider charge carriers being able to carry heat. As for electrons or ions, this attitude makes sense, since external electric potential drives particles with mass in a ...
0
votes
1answer
35 views
UV-VIS spectrometer on Solids
I ran an experiment using translucent single crystal solids. I modified the solids along the way using different chemical/temperature environments. After every stage, I ran the samples through a ...
1
vote
1answer
43 views
Understanding drift velocities in currents
I have a doubt about the understanding of drift velocities in a current. My problem is that the textbook speaks very loosely about this. It's like: "well, if we apply a field $E$ then the charges will ...
1
vote
1answer
101 views
What is crystal field anisotropy or effect ? It forces the magnetic moment to point in particular local direction..
Can you give a basic explanation of what is crystal field anisotropy ?
What is the reason to arise ?
In spin ice it forces the dipoles to point in the local 111 direction.
For partially filled rare ...
0
votes
0answers
93 views
What is the condition for getting Bose-Einstein condensation? [closed]
Consider an ideal Bose gas in three dimension with energy-momentum relation E proportional to $p^s$ with $s>0$. Find the range of $s$ for which this system may undergo a Bose-Einstein ...
0
votes
1answer
99 views
Does anyone know the difference and relation between $k\cdot p$ method and tight binding (TB) method?
Among the methods of calculating energy bands for crystals, first-principles method is the most accurate. Besides first principles, two commonly used modeling methods are the $k\cdot p$ method and ...
8
votes
3answers
315 views
Derivation of the “Bethe sum rule”
I am trying to work out the steps of the proof of the expression: $$\sum_n (\mathcal{E_n}-\mathcal{E_s})|\langle n|e^{i\mathbf{q}\cdot\mathbf{r}}|s \rangle|^2 = \frac{\hbar^2q^2}{2m}$$ from Eq. (5.48) ...
0
votes
1answer
40 views
Influence of the temperature on the ionization energies for impurities in silicon
Is there any dependence of the impurities ionization energy on temperature in silicon? I mean if there are any interactions between localized electron and phonons which leads to renormalization of ...
0
votes
3answers
399 views
Indirect band gap semiconductor for LEDs?
Can someone please explain why Indirect band gap semiconductor can not be used for LED creation. Can you also please give me some reference link for details.
2
votes
2answers
126 views
What's the differences among the concepts: binding energy, cohesive energy and formation energy?
In the papers about first principles (or ab initio) calculations, there are three energies which are often calculated: "binding energy", "cohesive energy" and "formation energy". Their meanings are ...
0
votes
0answers
9 views
use LPE mehtod instead of epitaxial in put graphene on silicon?
i want use LPE instead of epitaxial in put graphene on silicon can i do this work. here thickness of layer is nonsignificant.
1
vote
0answers
45 views
How is a Majorana fermion created when a s-wave superconductors is in proximity to a topological insulator (e.g. via an antidot)
Kane and Fu proposed a few geometries how to create Majorana zero modes using a s-wave superconductor in proximity to a 3D topological insulator (TI).
-> ...
1
vote
1answer
38 views
To which real densities do carrier densities in the semi-classical model of a crystal correspond?
In the semi-classical model of a crystal in solid state physics, electrons and holes are assigned effective masses that account for their different mobilities. E.g. in silicon, holes have a bigger ...
1
vote
1answer
53 views
What is paramagnetic current-current correlation?
I know what paramagnetism is. But first I want to know about the paramagnetic current and then the above-mentioned correlation?
Actually, I am working on a paper on superconductivity where I have ...
0
votes
0answers
40 views
Sommerfeld results & van Hove singularities
According to Sommerfeld the derivative of the density of states $g'(\varepsilon)$ apears in several thermodynamic quantities. Will this also be the case if one use the correct dispersion relation of ...
4
votes
2answers
135 views
Graphene +1 extra carbon bond
I'm not a physicist just a curious mind, so please go easy!
I was just watching a BBC Horizon Documentary that featured a piece on the recently discovered material Graphene. One of the facts ...
5
votes
2answers
2k views
The Spectral Function in Many-Body Physics and its Relation to Quasiparticles
recently, I stumbled accross a concept which might be very helpful understanding quasiparticles and effective theories (and might shed light on an the question How to calculate the properties of ...
1
vote
2answers
98 views
Eigenfunctions in periodic potential
For Hamiltonian $\operatorname H$ and lattice translation operator $\operatorname T$, if
$$\operatorname H\psi=E\psi, \qquad \operatorname T\psi=e^{ik\cdot R}\psi,$$
and
$$\operatorname ...
2
votes
1answer
71 views
What is the energy in eV between atoms in a typical solid state material?
Comps 2 question:
What is the energy in eV between atoms in a typical solid state material ?
Just rough estimate ?
How is that related to the thermal energy that needs to be supplied in order to ...
2
votes
0answers
154 views
Pauli paramagnetism for electrons with external magnetic field
Apparently it is to be shown that for electrons under an external magnetic field, in the limit as $B\to 0 $
$$
\chi = \frac{dM}{dB} \approx \frac{n\,\mu^{*^2}}{k\,T}\,\frac{f_{1/2}(z)}{f_{3/2}(z)}
$$
...
2
votes
0answers
76 views
What is Z3 exciton?
I am searching and studying excitons and I confronted with a term named Z3 exciton. What is it? And what is its difference with, for instance Z1 or Z2 exciton?
3
votes
1answer
96 views
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 ...
0
votes
1answer
96 views
Calculation of Number Density
Number density equation is given by
$ n= \dfrac{(N_A)\rho}{M} $
where
$ N_A =6.023\times10^{23} mol^{-1} $
$ \rho=8.02\ g/cm^3 $(at 1500 degree celsius.)
$M=63.546*1.6605\times10^{-24} g$
Whats ...
3
votes
0answers
99 views
Quantum Electrodynamics
I was wondering if anyone could give a simple explanation of how light interacts with matter. From what I have read in QED, electrons will repel each other because of their ability to emit and ...
