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.
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2answers
86 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, ...
7
votes
1answer
382 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 ...
6
votes
1answer
338 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 ...
5
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1answer
123 views
Intuition on topologically nontrivial 2D-band structures?
I want to get more intuition on topologically nontrivial band structures.
There's this popular 2D two-band model for a topological insulator
where $H=\sum_{k}h(\boldsymbol{k})$ (see Qi, Hughes, and ...
4
votes
1answer
142 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 ...
4
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1answer
52 views
Order of magnetic phase transitions
Is there any phase transition occur in paramagnetism to diamagnetism transitions state. What should be the order and how will I calculate the order?
2
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1answer
42 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 ...
1
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1answer
54 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 ...
1
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1answer
109 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 ...
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1answer
147 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
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1answer
121 views
What is electron momentum density in solids and molecules?
Can someone kindly help me to know how can i get electron momentum density for one orbital like home?
what is the theory of electron momentum density? how can I derive electron momentum density from ...
4
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0answers
128 views
What happens to a Luttinger liquid under time reversal?
Suppose you a have an ordinary Luttinger liquid with
$$ H = \int dx \sum _{\eta= \pm 1 , \sigma =\uparrow,\downarrow } \psi^\dagger_{\eta, \sigma} (x) (-i v \eta \partial _x) \psi _{\eta,\sigma} (x). ...
3
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0answers
48 views
Non-Hermiticity when Fourier transforming onto a finite lattice
I'm doing numerical simulations. I have the Haldane model in a honeycomb lattice where
$$ H = \sum \limits_{<ij>}a^\dagger_i b_j + h.c $$
Where $i$ belongs to sublattice $A$, and $j$ to ...
3
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0answers
69 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?
3
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0answers
105 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 ...
3
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0answers
72 views
Why do Fermi liquids have T^2 resistivity?
I have often read that metals that are Fermi liquids should have a resistivity that varies with temperature like $\rho(T) = \rho(0) + a T^2 $.
I guess the $T^2$ part is the resistance due to ...
3
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0answers
30 views
Are there any electro-optic crystals that are also pyroelectric but not birefringent?
As the title says, a crystal that is electr-optic and pyroelectric can it be non-birefrigent?
3
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0answers
66 views
Topological entanglement entropy only defined for a system in the ground state?
What happens to the topological entanglement entropy of a system, when it is driven out of its groundstate by increasing the temperature?
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0answers
83 views
Qualitative argument to determine energy of defects
In a book of "LES HOUCHES - Critical Phenomena, Random systems, Gauge theories" the author Frolich says that:
2D
In two dimensions, the mean energy of an isolated point defect in a square area of ...
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0answers
25 views
Is this a correct description of bonding in a metal?
I am reading the paper "Twenty five years of Finnis-Sinclair potentials" by Graeme Ackland, Adrian Sutton, and Vasek Vitek, Philosophical Magazine 2009, 89, 3111-3116. It is a review-type article ...
2
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0answers
243 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)}
$$
...
2
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0answers
49 views
Why does silicon have an indirect gap?
Is there an intuitive explanation as to why silicon has an indirect gap? I have heard that this can explained using pseudopotentials.
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0answers
69 views
Crystal momentum and the vector potential
I noticed that the Aharonov–Bohm effect describes a phase factor given by $e^{\frac{i}{\hbar}\int_{\partial\gamma}q A_\mu dx^\mu}$. I also recognize that electrons in a periodic potential gain a phase ...
2
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0answers
76 views
What is Z3 exciton?
I am searching and studying excitons and I confronted with a term named Z3 exciton. What is it? And what is its difference with, for instance Z1 or Z2 exciton?
2
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0answers
111 views
Stiffness tensor
Let's have a stiffness tensor:
$$
a^{ijkl}: a^{ijkl} = a^{jikl} = a^{klij} = a^{ijlk}.
$$
It has a 21 independent components for an anisotropic body.
How does body symmetry (cubic, hexagonal ...
2
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0answers
202 views
Simple model of edge states for a two-dimensional topological insulator
Quantum spin Hall states or, topological insulators are novel states of matter that have insulating bulk and gapless edge states. Are there any simple models that show these features?
See e.g. the ...
2
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0answers
101 views
Discrete sum over an exponential with imaginary argument, considering only every second lattice site?
Let's say I sum an exponential function $e^{\imath \left(k-k^{\prime}\right) x_{i}}$ over a chain system where every member of the chain is of the same type, e.g.,
A-A-A-...-A-A (total of N sites)
...
2
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0answers
136 views
What does plasmon look like in 3D band structure graph?
Consider metal, and its reciprocal lattice representation with Fermi surface.
What is the correct way to represent a plasmon in this system? M.b. rotating points on the surface? Or 3d membrane-like ...
1
vote
0answers
59 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).
-> ...
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0answers
33 views
Residual symmetries of the superposition of two fcc lattices
Fcc lattices are Bravais lattices and so are invariant under a set of discrete translations plus inversions over the 3 axis ($x\rightarrow -x$,$y\rightarrow -y$,$z\rightarrow -z$). When one superposes ...
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0answers
66 views
How to derive the divergence leading to Kohn anomalies?
I'm trying to understand the mathematical derivation given in the book "A Quantum Approach to Condensed Matter Physics" on page 215 (see 1), for explaining how the phonon-energy perturbed by ...
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0answers
78 views
Decomposition of elastic constants of a crystalline material
I have performed a calculation the tensor of elastic constants (or stiffness tensor) for a given crystalline material. From there, I calculated various elastic properties, such as Young’s modulus, ...
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0answers
170 views
Electron Fermi gas
My question is about 2-dimensional Fermi gas of electrons.
What is magnetic susceptibility when $T<<T_F$ (where $T_F$ is Fermi Temperature)
and,
What is the ratio between Pauli and Curie ...
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vote
0answers
372 views
Evaluation of band gap from transmittance
How can I evaluate the band gap of my ZnO thin film.
Thickness=d=80 nm
I’m aware of alpha=-1/d*log(T)
But I can’t fit a line to my data.
And: How can I smoothen my data on about 346 nm?
Do you have ...
1
vote
0answers
293 views
Fermi level in disordered amorphous and/or organic semiconductors
So, the Fermi level in crystals is pretty easy to understand. Been using it and talking about it in terms of the highest occupied level forever. However, I'm now reading about disordered systems. A ...
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0answers
14 views
Whether Au-Ga-Bi ternary phase diagram be calculated theoretically
Currently, my experiment involves the three elements: Au, Ga, Bi, and I need Au-Ga-Bi ternary phase diagram to explore the ...
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0answers
10 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.
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votes
0answers
46 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 ...
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0answers
97 views
Wave function ansatz for disclinated graphene with spin
I am currently investigating spin dynamics in disclinated graphene. More information about my approach can be found in my other post. I would like to know if my approach is somewhat correct to find ...
0
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0answers
111 views
Phonon Momentum
I am reading Charles Kittel's solid state physics and wondering what's the mechanism that neutron waves and photons can interact with phonons and the process obey the generalized momentum-energy ...
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0answers
20 views
Rice Allnatt distribution function
Can anyone give me an article of which explains Rice Allnatt distribution function or can you explain the function here?
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0answers
113 views
Phase diagram problem for ternary system
For a ternary system, three composites are present.
Temperature is also a variable.
Assuming that pressure is held constant, what is the minimum number of phases that may be present in a ternary ...
0
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0answers
34 views
Can one obtain saturation magnetization from FMR measurements?
Especially for magnetic thin films. Normally this is done by magneto-optical Kerr effect or SQUID measurements. Or is there a way to calculate the saturation magnetization based on other measured ...
