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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Hedin's equations and the ground state energy

Hedin's equations are an iterative scheme to calculate the Green's function $G$, the self-energy $\Sigma$, the vertex $\Gamma$, the polarizability $\chi$, and the screened interaction $W$. However,...
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Thermodynamic system, phonon and electron temperature and dissipation

Consider the following system (rudimental bolometer): A material (imagine a metal) A is initially at $25°\mathrm{C}$ and connected through Van der Waals forces to a material B (metal as well), which ...
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245 views

Can we call every pure solid a crystal?

What are pure solids? How many types of pure solids do we have? Are we still finding new pure solids or are these pure solids limited in number?
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Energy-band diagrams of heterojunctions

I'm studying heterojunctions and I'm struggling with drawing their energy-band diagrams. I've been looking for books or something to look up how the diagrams can turn out to be with different types of ...
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129 views

Question regarding NaCl equilibrium separation

So I am tutoring someone later and one of the problems is from Eisberg/Resnick Ch 12. The potential energy $V$ of NaCl can be described emperically by $$V = \frac{-e^2}{4\pi\epsilon_0 R}+Ae^{-R/\...
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Is the thermal conductivity of metals affected by magnetic fields?

Especially for a ferromagnet a magnetic field should have a field-induced band shift in the density of states but I wonder if this shift is big enough to be significant and affect the thermal ...
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28 views

what is the sharp step, terrace in stm image?

hi i`m interested in stm so i have read some paper about stm. but lack of my background, i have trouble with understanding. paper says that sharp steps, flat terraces and few serface imperfection ...
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830 views

What is the Fermi energy of (undoped) graphene?

All of the sources I have found for this online have been wildly unclear. Many use the phrase "Fermi energy" to refer to the "Fermi level" (which is emphatically not what I'm looking for; I want the ...
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18 views

Why does a higher gate voltage increase electron density + mobility in a 2DEG?

I have a question concerning a 2DEG created in a n-AlGaAs / GaAs heterostructure: If the n-doped AlGaAs is on the left side and the GaAs on the right side, the following band structure will appear: ...
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How exactly to build the band diagram for photonic crystal?

How to build a band structure for the photonic crystal? I'd like to understand the full train of thought. I understand that we go on the perimeter of irreducible first Brillouin zone and somehow copy ...
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1answer
134 views

What is the difference between Fermi level and Fermi edge?

Just as in title: What is the difference between Fermi level and Fermi edge? My friend makes some research about XPS and he encountered this term. He knows what is Fermi level, but never heard about ...
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827 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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56 views

Using the momentum-space definition of the position operator in position space?

For the position operator $\hat X$: $\hat X \rightarrow x$ in position space $\hat X \rightarrow i \frac{\partial}{\partial k_x}$ in momentum space Question: Can $\hat X \rightarrow i \frac{\...
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99 views

What are the key differences between a Wigner crystal and charge density wave?

We know that Wigner crystal is a crystal formed due to interaction(kinetic energy is quenched). It is a crystal of electrons and therefore has periodical oscillations in the charge density. Therefore ...
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Why does a cathode have to be heated to emit electrons?

Considering that electrons are highly mobile inside of a metal, why do they have such a tough time getting out at the edge of it and continuing their trip ballistically?
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37 views

Distance between adjacent planes in a crystal

This question has been asked before, but there doesn't seem to be a decent answer. Many sources state that " For cubic crystals with lattice constant a, the spacing d between adjacent (ℓmn) lattice ...
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What happens to a radar signal when it meets with a superconductor? [duplicate]

A radar system has a transmitter that emits radio waves called a radar signal, consisting of electromagnetic radiation. What happens when it meets with a strong superconductor, considering the fact ...
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226 views

Why polymeric solids are said to be intermediate between crystalline solids and amorphous solids?

Crystalline solids have ordered arrangement and amorphous solids do not. Polymeric solids are simply formed by the joining of some monomeric units. It has nothing to do with ordered or not ordered ...
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104 views

What is the physical meaning of an electronic system evolving adiabatically through a closed path?

I am trying to understand Physics behind the Weyl Fermion in Condensed Matter Systems. Electrons show Weyl fermionic behaviour in the vicinity of so called 'Diabolical Points' in the band structure. ...
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779 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 $ $$ \chi = \frac{dM}{dB} \approx \frac{n\,\mu^{*^2}}{k\,T}\,\frac{f_{1/2}(z)}{f_{3/2}(z)} $$ ...
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How to calculate the eigenstate of a lattice model in the position space

Say we have a triangular lattice, inside the unit cell there are four sites(label them as a, b, c, d) with different on-site potential energy. What I want to do is find the eigenstate in the position ...
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Why are magnetic quantum numbers assigned like they are assigned in the paper on WS2 monolayers?

Now I'm reading the following paper: Sie, E.J., et al., 2015. Valley-Selective Optical Stark Effect in Monolayer WS2. ‎Nat. Mater., 14, 290-294 And they assigned magnetic quantum number to valence ...
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909 views

Why is the law of the p-n junction valid under forward bias?

I'm currently studying the physics of the PN junction. I went though the derivation of the built-in potential in the PN junction under equilibrium: $$ {Diffusion\ current\ density} = {Drift\ current\ ...
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165 views

Coordinate system for crystallographic groups

In the International Tables for Crystallography for each crystallographic group an asymmetric unit is supplied (mathematicians call this a fundamental domain of the group). This region is a bounded ...
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1answer
305 views

What kinds of behavioural anomalies can a zero-field-cooled (ZFC) / field-cooled (FC) split indicate?

If a material shows a spiltting in the ZFC and FC curves, is it necessarily superparamagnetic, or could there be any other reason for the irreversibility? I have heard spin glasses also show ZFC-FC ...
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359 views

Question about electron-hole pair generation in depletion layer for a p-n junction photodiode

At the heart of operation of p-n (or p-i-n) junction photodiodes is the absorption of photons leading to generation of electron-hole pairs. If the diode is, e.g., reverse biased, then the motion of ...
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224 views

Do indirect optical transitions “cool” the material a little?

So I'm reading in Ashcroft and Mermin about indirect optical transitions: So, a photon comes in, and it only excites the electron across the indirect band gap if a phonon with the appropriate wave ...
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190 views

Is carrier charge density and carrier mobility constant in a given material?

If we assume the semi-conductor is doped by a variable amount, is there some way I can look up carrier charge density for the material in a reference somewhere? What about carrier mobility?
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The two point fluctuation autocorrelation function in computing the scattering intensity?

In this paper: http://www.pnas.org/content/113/8/2029.full.pdf?with-ds=yes and: http://www.pnas.org/content/113/8/2029.full.pdf The authors try to compute the scattering intensity for a simulation ...
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35 views

Stoner-Wohlfarth model for ferromagnetism

I'm studing the Stoner-Wohlfarth model for ferromagnatism on the book Ibach-Luth Solid state physics. During the derivation of the Stoner criterion I found this passage (8.43) not so clear for me: ...
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3answers
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Mean energy of free electrons

My textbook states that the mean energy of free electrons within a solid state is given by $$ E_{av} = \frac{U}{N} = \frac{\int_0^{k_f}D(k)E(k)dk}{\int_0^{k_f}D(k)dk} $$ where $D(k)$ is the density of ...
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565 views

How should I think about reciprocal lattice and Miller indices?

When I hear someone talking about a (100) plane or a (111) plane or an (hkl) in general, my first thought is, is the system cubic. The reason I think this is because I tend NOT to think of the planes ...
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Projected band structure plot - orbital characteristics plotted vs the K values?

I'm not understanding what is it that I have to plot for obtaining the orbital characteristics of a band in the band structure diagram. Usually we plot the energy eigenvalues for a given k point. ...
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130 views

Simple Explanation of Kondo Effect

Does anyone have a simple explanation of the Kondo Effect? (i.e. a simple physical picture + maybe equations to think of?) My current understanding is this: If we consider an electron scattering ...
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49 views

Where can I learn about band theory?

I'm studying quantum mechanics and I want to understand perfectly where the bands of the electronic sturcture come from. I've read that it is related with the periodic potential, Bloch waves and ...
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150 views

Separating the hamiltonian for a superlattice — is it this easy?

I've been banging my head against a wall trying to figure out what I'm sure is a very simple problem. I want to solve the Kronig Penney model for a superlattice, which is just a normal periodic 1D ...
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310 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 ...
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Hamiltonian formulation of the semiclassical Model of electrons

I'm currently reading the book Solid State Physics by Neil W. Ashcroft and N. David Mermin. In Chapter 12 they introduce the "Semiclassical Model of Electron Dynamics". In short: After having solved ...
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Why don't FCC metals have a brittle-to-ductile temperature transition?

I initially thought that it had something to do with the number of slip systems in FCC vs. BCC, but they're both the same.
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Why does Fermi Level change due to change in donor atom concentration?

Suppose I have a n-type semiconductor whose fermi-level lies (say) 0.2 eV below the conduction band. Why would this level change if I changed the doping by making the donor concentration (say) 4 times ...
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Temperature dependence of the relaxation time in Boltzmann equation for impurity scattering in metals

Is there any temperature dependence of relaxation time in impurity scattering of conducting electrons? It seems to me that there is none. But, some people claim that there is. So if you could explain,...
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1answer
345 views

Atomic nearest neighbor notation

I recently got a correction to a paper that I am writing. The correction references a section in which I talk about nearest neighbors. The comment says: Do you mean NN, NNN, etc., or NN, 2NN, 3NN? ...
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Why the cooper pair do not obey the exclusion principle?

In superconductivity, which occurs in certain materials at very low temperature, electrons are linked together in cooper pair. And why the cooper pair do not? Thank you in advance.
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Classical Mechanics as an approximation of Quantum mechanics [closed]

I want to show an equality: We know from Ehrenfest's theorem that $$ \frac{d \langle x \rangle(t)}{dt}= \left\langle \frac{\partial H}{\partial p} \right\rangle $$ I'd like to derive the ...
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246 views

How does crystal lattice explain electrical conductance?

From http://education.jlab.org In a metal, the atoms are arranged in a crystal-like configuration. ... Now, in a metal, the valence band is relatively close to the conduction band - ...
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Connection between Bragg diffraction off BZ planes and opening of a band gap

I have a hazy idea that comes from a few video lectures where the following is stated: The condition for constructive interference (Bragg condition) in reciprocal space is that the wave vector should ...
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Eigen energy of the Landau levels in a tilted magnetic field

The problem pertains to a fermi gas in a tilted magnetic field confined by a harmonic potential in the z direction. I chose the vector potential $(0,ax-bz,0)$. I obtain the following hamiltonain with ...
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Any good books on the physics of semiconductor devices?

I know there are many books on semiconductor devices. But, it seems that many of them are catering to the engineers, not physicists. Namely, the books lack the theoretical depth. So, is there any ...
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392 views

Bragg diffraction and lattice planes

Crystalline substances show, for certain sharply defined wavelength and incident directions, very sharp peaks of scattered X-ray radiation. From the illustration below we see that we get constructive ...
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What is the difference between crystals and solid? [closed]

In condensed matter physics, what are the differences between crystals.