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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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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What is the difference between crystals and solid? [on hold]

In condensed matter physics, what are the differences between crystals.
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Can Non-Magnetic Dust Particles become magnetic if their particle size is decreased (by grinding them probably)?

Problem: Take some dust particles whose size is big. Bring a magnet near them. They do not get attracted to the magnet and thus we conclude that they are non-magnetic. However, when you grind the ...
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Why Weyl fermion in Weyl semimetals(WSM) have high mobility only at low temperature?

I read several papers reporting high Weyl fermion with very high mobility in WSMs such as TaAs, NbAs, WTe2 and so on. However, this high mobility looks like (=Weyl fermion) always appears at only low ...
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3answers
52 views

Could dark matter possibly be anti-matter?

Considering the broken symmetry after the big bang - what I understand as there being a huge surplus of matter and a lesser presence of anti matter - is it possible that dark matter could be anti-...
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Resistance increase with length because of more scattering?

I am referring to one of the answers to this old question. I can't add comment to it because I don't have enough reputation. So here I rephrase the question: does resistance increase with length ...
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How do i calculate leakage current in passivation layer of GaN HEMT?

I want to calculate the leakage current between the passivation and encapsulation layers of the GaN HEMT which will give me information about the material
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39 views

Why does AC Conductivty in Drude Theory have an Imaginary and a Real Part?

In the Drude Model the direct current (DC) conductivity is given by the following formula: $$\sigma_0=\frac{ne^2 \tau}{m}$$ where $\tau$ is the relaxation time. Furthermore, the AC conductivity in ...
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Third Brillouin zone for a quadratic 2D lattice

As far as I understand, the construction of Brillouin zones stems from the relation $$ 2 \vec{k}\cdot \vec{G} +G^2 = 0$$, where k is the wave vector and and G is the reciprocal lattice vector. This ...
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Landau Diamagnetism and Pauli paramagnetism

In the conventional definition of Landau's diamagnetism we ignore the effect of spin-electron coupling and vice versa for the derivation of Pauli's paramagnetism. I want to know what would happen if ...
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23 views

Out-of-plane electronic band structure for 2D materials?

There's been much recent interest in 2D materials since they can form monolayer-thick films. Since their crystal structure is periodic along the in-plane directions, the electronic band structure ...
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Solid state physics: When do I use classical laws?

Let's say I am given the dispersion relation for nearly-free electrons: $$ E(k) = \frac{\hbar^2}{2m}(k^2+c\,k^4)$$ Where $c$ is a small constant of appropiate dimension. How do I calculate the ...
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How do signals go through solid objects? [closed]

So many types of signals pass, or seem to pass I don't know, through solid objects. How do they do this?
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54 views

Intuition for defining basis for Hamiltonian in momentum representation

I am going through Quantum information approach to the Ising model: Entanglement in chains of qubits by Stelmachovic et al. In Section A.4, the authors determines the eigenvalues and eigenstates of ...
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40 views

Speed of sound in solid — temperature dependence

Let $v$ denote the speed of sound in a fixed solid, at a fixed temperature $T$. This will depend on properties of the solid (such as the bulk modulus and density). Given an increase in $T$, does $v$ ...
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21 views

Deriving Reciprocal Lattice Definition

The derivation of reciprocal lattice vectors in terms of the direct space lattice vectors starts by applying expanding a translationally invariant lattice function $f(\bf{R_k}+r)$ in plane waves $f_k ...
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Bosonization for unequal left/right Fermi velocities

The standard exposition of bosonization/Luttinger liquid theory in textbooks treats the case that left and right channels share the same absolute value of Fermi velocity. Is it possible to relax this ...
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17 views

How to confirm experimentally the effect of momentum space Berry curvature in solids?

I'm studying spin-orbit coupling and Berry curvature effects, especially on the spin Hall effect. However, Table 3 in a review paper http://journals.aps.org/rmp/abstract/10.1103/RevModPhys.87.1213 ...
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How can I derive the Phonon Density of Normal Modes in two and three dimensions?

The density of normal modes in 1D has already been discussed in another post (LINK) In essence, the formula is: $$D(\omega) = \frac{1}{2\pi}\int\mathrm{d}q\,\delta(\omega-\omega(q))$$ resulting in ...
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The d-orbital splittings in WS2 monolayer

According to this paper (and many others), the formely degenerate $d$ orbitals of the tungsten atoms in the $WS_2$ monolayer are split into three groups: (1) $d_{z^2}$, (2) $d_{x^2-y^2}, d_{xy}$ and (...
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134 views

Particle density in k-space

Question: Given a many particle wave function $|\Psi\rangle$, how can I calculate the occupation numbers in k-space? Setup: I have a 1D chain of molecules which contains 4 sites per unit cell. Let'...
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37 views

C libraries for Solid State Physics

During last year I've attended courses of solid state physics, and I studied methods for bands structure calculations in the Hartree Fock framework. However, I know only theoretical aspects of these ...
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1answer
39 views

Bands in semiconductors: $E$ vs. $k$ diagram

I always thought that in a semiconductor there was one gap, one conduction band and one valence band. However, reading a book I came across this picture And now I'm very confused. Apparently there ...
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42 views

Connection between fractional charge and Schrodinger's cat

In the FQHE, it is said that one electron splits into three 1/3-charged entities. Is it like the Schrodinger cat?
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Density of States for a separable hamiltonian

There are $N$ non interacting electrons in a potential well: \begin{align} H&= -{1 \over 2 } \nabla^2 + U(x,y,z) \\ U(x,y,z)&={1\over2}\omega^2z^2 \; \mbox{for} \; (x,y) \in [0,L]\times [0,L]; ...
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At most $N$ gapless charge/spin modes in a system of $N$ coupled 1D chains?

Leon Balents and Matthew P. A. Fisher claimed the following without any further explanation ($N$ is the number of chains) For a system of $N$ coupled 1D chains, the number of gapless charge modes ...
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Why can we extract the oxidation state from XPS and XANES but not from XRF or EDX?

To my understanding it is possible to extract information about the valence/oxidation state of an ion in a material by using X-ray photoelectron spectroscopy (XPS) or X-ray absorption near edge ...
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38 views

Simplifying three mass, two springs system

I have a system of three equal masses connected by two equal string system. x_1 x_2 x_3 *--------*---------* ------> x M k M k M ...
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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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what is the physical significance of dielectric constant and loss tangent?

I want to know that the significance of dielectric constant and loss tangent behaviour. How it characterises the materials. and possible relation between the dielectric constant and polarisation ?
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30 views

Why the direct band gap semiconductor get higher optical absorption coefficient than indirect band gap semiconductor

I can understand that direct band gap semiconductor doesn't need phonon to absorb light. But in the following formula: Optical absorption coefficient is proportional to the square of hv in indirect ...
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1answer
19 views

Is a typical glass slide really amorphous or does it just have very small crystallites?

I heard today that there's not really any true amorphous materials; that the theoretical concept (no level of ordering whatsoever) exists of course, but that no materials are 100% truly random and ...
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Finding Miller index

When a beam of electron hits a crystal and come back at some angle, how we calculate the plane from which it reflects (let us consider it reflects). i mean what is the miller index of the plane?
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Non-constant Bandgap in a semiconductor

For a material made of two different intrinsic semiconductors (SC); $SC_A$ on the left, and $SC_B$ on the right, such that $E_{gap,A}>E_{gap,B}$, the energy band diagram would look like so: Note: ...
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970 views

Is it possible to have solid light? [closed]

Is it possible to have solid light? If so, what would it be like?
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28 views

How are you the special points/critical points in the Brillouin Zone pronounced? [closed]

I know that this isn't exactly physics, but I don't know where to ask. http://en.wikipedia.org/wiki/Brillouin_zone#Cubic_lattice_system_CUB.281.29.2C_BCC.281.29.2C_FCC.281.29 The critical points/...
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Electronic or excitonic band structure?

Usually, in the papers the electronic band structure for monolayers $WS_2$ is something like in the figure below: As you can see the direct bandgap is around ~2.0 eV. When we excite electrons at the ...
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Direction of momentum given by the de Broglie relation

The momentum of an electron can be computed by the well-known classical mechanics equation: $p=mv$ where $m$ is the mass of an electron, and $v$ is its velocity. In this case, since $v$ is a vector,...
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1answer
64 views

Is zero heat capacity possible without violating the third law of thermodynamics?

Suppose we have a gapped system i.e. no gapless excitation is possible. If the thermal energy is insufficient to excite atoms from ground state to excited state of any kind (of a single atom or of a ...
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Miller indices and distance between parallel planes in a cubic lattice

I have been learning about the Miller indices of a lattice plane and how to use them to find the distance to the nearest parallel lattice plane in a Cubic lattice but I must be getting something wrong....
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81 views

Dispersion relation for lattice vibrations: Why are there two and not four solutions?

A linear chain of diatomic molecules can be modeled by a chain of molecules with different spring constants $C_1$ and $C_2$ (See Figure) The corresponding equations of motion are: $$M\ddot{u}=-c_1[...
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1answer
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Why does the band gap decrease when the thickness of the material increases?

Thin films of material (monolayers, etc) tend to have higher band gaps than their bulk materials. This is true for a wide range of materials. What is the reason? Is it due to the fact that there is ...
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Experimental confirmation of the finite jump of the occupation number at the Fermi surface

It is a well-known result in Fermi-liquid theory that the occupation number has a finite jump at the Fermi surface. But, is it confirmed experimentally?
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Why are numbers not consistent? (Identifying phonon's frequency)

I am trying to connect several facts between each other to acquire a consistent picture. Fact 1. Monolayers of tungsten disulphide $WS_2$ have hexagonal crystal lattice, and the first Brillouin zone ...
3
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1answer
80 views

Fluctuation-dissipation theorem in QFT

If I understand correctly, the fluctuation-dissipation theorem (fdt) in QFT technically arises because of $\pm i\epsilon$ - infinitesimally small summand in the denominator of spectral representation ...
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33 views

Is it feasible to store large amounts of information on DNA molecules (for years)?

This initially might seem like a biology based question, but I want to concentrate on the physics of DNA molecules, used purely as a manmade stable substrate for storing information. A 2013 Ted Talk ...
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Question about the Luttinger liquid

I am learning Luttinger liquid now. It is a very basic question, I think. Look at the figure. For each $k $, there is a state for the left mover and a state for the right mover, right? They have the ...
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Solutions for Kittel's Introduction to solid state physics 6th edition?

I'm looking for the solutions of Kittel's 'Introduction to solid state physics' 6th edition. I can only seem to find the solutions for the 8th edition online. Does anyone have the pdf to it? Or ...
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Is this a valid way for deriving the ODE for a lattice vibration of a one dimensional crystal?

Consider the following lattice: I want to derive a differential equation that describes the forces acting on the $n$-th atom in the lattice. Each atom is coupled to its neighbour ($n+1,n-1)$ by a ...
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Why can the dispersion relation for a linear chain of atoms (connected by springs) be written as $\omega(k)=c_s \lvert k\rvert$?

On the german wikipedia site (right under "Akustische Moden"), the dispersion relation for a linear chain of atoms (connected by springs): $$\omega(k)=2 \sqrt{\frac{K}{M}} \left \vert \sin{\frac{ka}{...