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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Quasi-fermi levels in a solar cell?

I was wondering, if my fermi levels splits up due to n and p type doping into two fermi levels, one for the p type one for the n type, and now due to light radiation my fermi levels split up into 2 ...
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potential decomposition in terms of Bloch eigenstate

Given a single particle Hamiltonian $H=-\frac{\hbar^2}{2m}\nabla^2+V(r)$, where $m$ is the electron mass and $V(r)$ is a periodic function representing the lattice potential. It is defined in the ...
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23 views

Expression for spontaneous emission in solids

I have yet to find a reliable source for the expression of the rate of spontaneous emission in a solid. Can anyone confirm if the following is correct? The basic ingredients of the calculation are ...
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Different electrons, why aren't they all the same?

Why do we say that there are different kinds of electrons when discussing different situations in physics? For instance the Weyl electron, Dirac electron etc. From my exceedingly basic knowledge isn't ...
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Can any one explain how to obtain the frequency distribution versus density of state, from dispersion relation? [duplicate]

How to compute phonon frequency spectrum or ohinon distribution of an element.
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Transition Capacitance & Diffusion capacitance of a diode

What are Transition and Diffusion Capacitances of a Diode? Why is Transition capacitance more significant in the reverse bias condition? Why is Diffusion Capacitance more significant in the forward ...
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Definition of luminescence

I saw a definition of luminescence as "any light not resulting from blackbody radiation", but in my view it's too broad. Is an accelerating electron producing luminescence? Or an electron recombining ...
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Is there a way to get the Bethe Roots, that belong to a given eigenvalue of the transfer matrix?

(Quantum) integrable systems, that belong to solutions to the Yang-Baxter-equation, are often solved by the (algebraic) Bethe Ansatz. Solutions to the Bethe-equations lead to the eigenvalues of the ...
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Connection between fermi velocity and mean (square) velocity of diffusion current

Is there any connection between $v_{F}$ and the $<v^{2}_{diff}>$, lets say for electrons in metals? I have come to a conclusion, that they are the same order of magnitude and their equivalence ...
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Fermi Level: chemical potential vs. electrochemical potential

In solid-state physics it is understood that the Fermi-Level is the electrochemical potential. The Fermi-Level is defined to: However, in thermodynamics this formula is referred to as the ...
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Light (Laser) operated optical switch

I have searched the web and found that optical switches are activated either through mechanical or electro/magnetics. Making them sort of Optomechanical or optoelectronic switches. Lets exclude ...
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After being heated and cooled why does Coconut Oil form these structures?

According the the guy who posted this picture, the coconut oil melted during a heatwave and then re-solidified into hexagonal structures. I looked into foam physics and it seems that area deals ...
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about Conservation laws and Correlation function

I'm reading a review paper by Gorden Baym-(http://www.worldscientific.com/doi/abs/10.1142/9789812793812_0002) In the second part, he raised that: According to conservation law $\frac{\partial ...
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How can a phosphorous ion dope silicon when it is already ionized?

In ion implantation dopant ions are directly bombarded into the semiconductor (silicon for example)? But if say P ions (P+) were implanted then it does not have an extra electron to donate into the ...
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54 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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Why does circularly polarized light break time-reversal symmetry?

I've encountered some interesting paper on 2D materials where authors use circularly polarized light to break time-reversal symmetry to split energy levels. Here you can find the paper: ...
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What keeps charge from “spreading” in a CCD pixel?

In a CCD, you generally have a photosensitive substrate (e.g. n-doped silicon) that is attached to a network of electrodes that, after exposure, will move the charge, allowing the CCD to be "read". ...
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What does “fully depleted” mean?

In many papers/articles on CCDs, particularly those used for dark energy surveys and dark matter detection, the term "fully depleted CCD" is used. What does this mean? References: ...
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Transperancy of Solids [duplicate]

Why are some solids opaque and others transparent? If electrons are omnipresent in matter then how does light pass through them without colliding?
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Spatial probability density of single atom in a crystal at low temperature?

I'm working in gravitational physics, unfortunately my solid state physics lecture is already a while a go. My question will probably sound quite trivial to solid state physicists, but I couldn't find ...
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How would the fermi energy of an element inside of crystal affect its fermi level?

If I had a substitutional crystal of nickel atoms inside of a copper fcc lattice, how would this affect the Fermi level of the material?
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Bloch waves at large momenta

I am trying to come to grip with some solid state theory. Bloch waves, energy eigenstates for hamiltonians with lattice periodic potential in $\mathbb R^d$, are frequently written as ...
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What is the electron barrier tunneling mass, and why it is necessary? What is the ebarrier tunneling mass of AlGaAs?

I am doing solar cell simulations in synopsys software. I am getting a persistent error saying ebarrier tunneling mass has not been defined. Is anyone familiar with this error? What is this ...
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Relaxation time approximation in anisotropic potential scattering event

In relaxation time approximation (RTA) of Boltzmann transport theory, the relaxation time is calculated by $\frac{1}{\tau(\mathbf{k})}=\frac{2 \pi}{\hbar V}\sum_{\mathbf{k^{'}}} \delta ...
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Why the optical gap is not identical to the charge gap?

The optical gap is the photon energy required to create an exciton (in a solar cell for example). The charge gap (aka electrical gap) is the energy (voltage) required to create a photon (in an LED for ...
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Fermi Level difference effect on thermionic emission in an open-circuit

The circumstances in which I am asking this: I have two materials, copper and cesium, in which the surface of the two are contacting. The Fermi Energy value for copper is 7.0eV and for cesium it is ...
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How will open-circuit voltage affect the Fermi Level Difference

The circumstances of my question consists of this: I have two materials, copper and cesium, and they are sandwiched together with a layer of cesium in the middle. It is connected only on a single side ...
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Perturbation theory in second quantization

I am dealing with electron/phonon interaction in QM. In particular, given the Hamiltonian of a solid, $$H=H_{el}+H_{ion}+H_{el-ion}$$ we have that the el-phonon Hamiltonian is treatened ...
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Number of classical oscillation modes of a Lattice and number of quantum phonons

In solving the Classical model for lattice dynamics [Rossler pag 38] we find that the lattice admits $$d\cdot N\cdot r = \#modes$$ where $d=$dimension of the problem $N=$ number of atoms $r=$ ...
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Double groups in Crystallography

I'm currently studying double point groups and their applications in condensed matter physics. Let me start by giving you the definition of the double group that is used in my textbook: Let $G$ be a ...
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What causes the Shubnikov-de Haas Oscillations?

If I have a 2DEG with a voltage in the $x$-direction and a $B$-Field in the $z$-direction (so I also get a hall-voltage in the $y$-direction (classicaly)). But if I do this stuff at low temperatures I ...
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Why do we assume electrons experience lattice potentials in solids?

Why don't we assume the protons wave function spreads out uniformly and just provides a uniform background potential?
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40 views

Resistance of a cloud of free electron gas by Kubo formula?

How much is the resistance of a cloud of free electron gas, if at all? How much is the resistance of a cloud of free electrons in a periodic potential? Did anyone calculate it using the Kubo ...
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Topological insulators literature

I started learning things on topological insulators and I got lost in dozens of existing papers on this topic. Could anyone recommend me appropriate literature that explains deeply enough what ...
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Nature of photoluminescence at a semiconductor heterojunction

Do I understand it correctly that photoluminescence at a semiconductor heterojunction occurs because of intralayer recombination? If so, why can't photoluminescence occur because of interlayer ...
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e-e scattering time in graphene

I think its worth writing my second question in this post as a separate one. In normal Fermi liquid, the electron-electron scattering time $\tau_{e-e}$ is about: $$ \tau_{e-e} \approx \frac{\hbar ...
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Repulsive component of intermolecular interaction

Intermolecular interaction mainly consists of 2 components: (a) Dipole vs dipole (permanent & induced), which is more likely to be attractive (b) Pauli exclusion, which is always repulsive The ...
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Basic questions about the Kitaev chain

I am trying to understand the first 5 pages of Introduction to topological superconductivity and Majorana fermions http://arxiv.org/abs/1206.1736 I read it 2-3 times and thought about it but a few ...
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Matsubara Green function of anderson impurity model

I am currently having trouble computing the imaginary-time Green's functions of a model similar to the single-impurity anderson model. The hamiltonian is given as: \begin{equation} H = ...
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1answer
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How can crystal symmetry operations be used to reduce the number of unique properties of a solid?

Can anyone please give an example or a reference which shows how crystal point groups and symmetry operations can be used to reduce the number of parameters describing the property of a crystal, ...
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59 views

e-e scattering rate in normal fermi liquid and in graphene

In Ashcroft/Mermin's solid state physics, in equation (17.64) they argued that: We expect from lowest-order perturbation theory (Born approximation) that $\tau$ will depend on the ...
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About the definition of the spin current

People have been talking about the spin current for a while. But there is a fundamental problem. Unlike charge, or mass, spin is not conserved. Let us take the 1d spin-1/2 Heisenberg chain as an ...
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Why are bandstructures plotted only along certain symmetry points?

Why is it that bandstructures are usually represented along certain symmetry points ? What determines these symmetry points ?
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DOS integral when surface is not closed

According to the density of states (DOS) formula $$\rho(\varepsilon)\propto \int_{\varepsilon=\text{const}}\frac{dS}{|\nabla_k \varepsilon_k|}$$ Since there is an integral on the constant energy ...
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DOS behavior of Van Hove singularity in a line

When there are some points in momentum space give $|\nabla_k \varepsilon_k|=0$, they are called Van Hove points and give singularity in the desity of states (DOS). But what if $|\nabla_k ...
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DOS of Van Hove singularity in 2D square lattice tight binding model

For the simplest example, 2D square lattice tight binding model gives the energy band as $$\varepsilon_k=-2t(\cos k_x+\cos k_y) \, .$$ We know that $\vec{k}=(0,\pi)$ and related momentum points are ...
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How to get DOS of Van Hove singularity using quadratic dispersion relation

Take 2D case for example. We can first get the area in momentum space for all $k$ that satisfy $E_0<E(k)<E $, say $S(E)$. And the density of state (DOS) is $\rho(E)=\frac{\partial S(E)}{\partial ...
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How to get the asymptotic expression of DOS near Van Hove singularity [duplicate]

For the simplest example, 2D square lattice tight binding model gives the energy band as $$\varepsilon_k=-2t(\cos k_x+\cos k_y) \, .$$ We know that $\vec{k}=(0,\pi)$ and related momentum points are ...
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Fillings of dispersion bands (E-K diagram)

I struggle in understanding why in some references the bands filling by electrons in the E-k diagram is shown as an area delimited below by the dispersion curve and above by the Fermi energy (if in ...
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Dispersion in crystall for a random direction

Lets say one get a dispersion of electrons or phonons from this website: http://www.matprop.ru Usually dispersion in particular directions is drawn: as for wurtzite crystall it is A to L, L to U and ...