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Questions tagged [solid-state-physics]

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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Does change in the centre of gravity affect weight and if so how

A mason on a ladder standing in a pit of mud realises that as he scales up the ladder it starts to sink whereas at his original position ( bottom of ladder) it did not sink.Explain how without ...
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Can the total energy of a solid be measured with photoemission?

Angle resolved photoemission spectroscopy (ARPES) is a really popular tool developed to study the behavior of solids by looking at the behavior of their photorlectrons. This is used to measure ...
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How to find energy levels formula for symmetric triangular potential well [on hold]

As some of you already know that the asymmetric triangular potential well has the energy level where an here refers to the airy function a1 =2.338, a2=4.088, a3=5.521 and a4= 6.787 and V=eFz (F here ...
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Where is the missing energy in the Debye-Waller effect?

X-ray/neutron scattering from crystals and liquids is well-described by the scattering theory to give the (dynamic) structure factor which is a function of momentum and energy: $$S(\mathbf{k},\omega)=...
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Dispersion relations in solid state physics

Could you please explain what exactly is the relevant information that is conveyed through a dispersion relation? Edit 1: Sorry about being vague. I am currently trying to understand the dispersion ...
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what are 2D point groups with respect to a 2D lattice

I am having trouble understand how you calculate the point group of a 2d lattice, I am currently reading 'Solid state physics' by J.R.Hook and H.E.Hall and the book talk briefly about point groups and ...
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Does the sequence of the $n$th Brillouin zones converges to any particular geometrical form?

I am currently studying solid state physics and we just saw the construction of the Brillouin zones. My question is the following: Does the sequence of the $n$th Brillouin zones converges to any ...
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Identity when Diagonalising Single-Particle Hamiltonian

Sorry the title is not precise; wasn't sure how to make it so (this is perhaps a straightforward question). The following is an identity I see quite often when reading lecture notes about ...
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Number of allowed (phonon)wave vectors in a poliatomic-basis lattice?

Lets say that my crystal is of size $N=N_1N_2N_3$ , this is the typical textbook example and after that they say that the number of allowed wavevectors is N. But tbh I dont really know if they are ...
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Using FFT for spins in a non-cubic crystal lattice

Classical Ising/XY/Heisenberg models on a crystal lattice are commonly used to model magnetic materials. These can be studied using Monte Carlo simulations on a computer. Magnetic systems are often ...
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Reduced wave vector using Bloch's theorem

In every solid state physics book it says that the wave vectors appearing in Bloch's theorem can be confined to the first Brillouin zone and provide a hint on how to show this. Most of the times this ...
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Energy bands. Bonding and antibonding orbitals

In tight-binding wikipedia article it is said that bonding and anti-bonding orbitals correspond to different $k$-values in a single energy band. At the same time in Cordona Fundamentals of ...
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Is this equation for the density of states of an elastic isotropic material an approximation?

The density of states of phonons can be calculated with $$ Z(\omega)=\frac{V}{(2\pi)^3}\int_{\omega=\text{const}}\frac{d\vec{f}_\omega}{|\vec\nabla\omega|} $$ where $\omega$ is the phonon frequency ...
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Is there a mathematical way to find the lattice points in a crystal?

In my solid state physics class we need to be able to determine the number of lattice points per cell of various Bravais lattices. For example, the orthorhombic which has 4 lattice points per cell. I ...
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Constant density in Sommerfeld model

In chapter 2 of Ashcroft and Mermin's Solid state physics we reach this expression of the electron energy density: $$ n=\int_{0}^{\varepsilon_{F}} g(\varepsilon) d \varepsilon+\left\{\left(\mu-\...
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Van der waals forces interaction

My slides say: A gas with low density in which you can consider the attractive energy the sum of the isolate atoms couple $$ u=\int^S_\sigma{4\pi\frac{N}{V}}\left(\frac{\beta}{r^6}\right)r^2\...
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Lattice structures of two and 3 atoms basis

I seem to be having a real issue in how people instinctively know how to draw a unit cell lattice structure for 2 and 3 atom basis from vector points given. So two typical example that I have been ...
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Splitting of energy levels in solids [duplicate]

when atoms are well seperated energy spectrum is discrete, but when they come together energy levels split and they form bands, upto this i can understand. where im confused is that these splitting ...
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Numerical exact diagonalization of tight binding Hamiltonian

I want to exactly diagonalize the following Hamiltonian for $10$ number of sites and $4$ number of spinless fermions $$H = -t\sum_i^{L-1} \big[c_i^\dagger c_{i+1} - c_i c_{i+1}^\dagger\big] + V\sum_i^{...
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What is the relation between chemical potential and the number of particles?

Chemical potential is defined as the change in energy due to change in the number of particles in a system. Let we have a system which is defined by the following Hamiltonian: $$H = -t \sum_i^L c_i^\...
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Is it possible to generate Ampere's force between the superconductor and the current-carrying wire?

In superconducting state, There is a current-carrying wire between the superconductor and the magnet,Is it possible to generate Ampere's force between the superconductor and the current-carrying wire?...
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A computation problem on reciprocal lattice

I am reading David Tong’s lecture notes on Application of Quantum Mechanics. My confusion is about the following paragraph: Consider a function $f(\vec{x}) $, suppose $f(\vec{x})=f(\vec{x}+\vec{r})$...
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Drawing reciprocal lattice structures

I am currently trying to understand why and how reciprocal lattice relates to the diffraction plane, so I did some research on Wiki about reciprocal lattice, but I seem to be stuck as I would like to ...
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How does one construct the $n$th Brillouin Zone in a rectangular lattice geometrically?

What are the general rules of constructing the Brillouin Zone in a rectangular lattice geometrically? While the construction of the 1st and 2nd Brillouin zone is rather simple, starting to construct ...
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What does the “lowest order adiabatic approximation” mean?

I came across a concept "lowest order adiabatic approximation" in solid-state physics. I searched and found dozens of "lowest order adiabatic approximation". I think the "lowest order adiabatic ...
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density of state function for semi Dirac materials

Respected members I have a problem in finding density of state for semi Dirac system (linear dispersion relation in one direction and parabolic in other direction). $$E(k)=\pm\sqrt{{(\hslash^2k_x^...
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Charge carriers type: contradiction between Hall effect and Seebeck effect, how to resolve it?

On one hand the Hall effect consists of a voltage that arises when an electric field and a perpendicular magnetic field are in a material. This makes the charge carriers (electrons or holes) under the ...
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Plasma Frequency of Indium Tin Oxide

What does determine the plasma frequency? The formula is: $\omega_p² = \frac{4 \pi N e²}{m}$ and for frequencies above the plasma frequency the material is transparent. So for Indium Tin Oxide the ...
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Terminology Trouble with respect to lattice structures

I am having an issue understanding terminology in a chemistry text book I am reading. I am reading about lattice structures and it keep interchanging with the word 'basis'. So for context, it ...
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33 views

Wave scattering by crystals

The structure factor is defined as (assuming orthogonal axes): $$S_{(hkl)} = \sum_{j \in \mathcal{U}} f_j \exp\{2\pi i (hx_j+ky_j+lz_j)\},$$ where $\mathcal{U}$ is a unit cell of the lattice and the ...
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Why we can't write low energy effective field theory for a gapless system?

Assume that we have an Hamiltonian $$H=H_0+H_{int}$$ where $H_0$ has gappless excitations and $H_{int}$ has usual two body interactions. If $H_0$ were gapped I would able to get low energy effective ...
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Reciprocal lattice of fcc or bcc

If we want to find reciprocal vectors/points in reciprocal space of a bcc or fcc lattice we often use the non-primitive lattice vectors of the ordinary cubic (reciprocal) lattice. Looking at families ...
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Lattice structure of diamond

The previous question was about whether diamond can be described by an ordinary cube lattice instead of a FCC lattice. I now know that this is possible since we can still get the whole crystal in this ...
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Question about Eq. 10.9 in Ashcorft and Mermin

I have a doubt concerning the assumptions made in deriving Eq. 10.9 in Ashcroft and Mermin's Solid State Physics text. We have two entities in the equation: $\psi_m (\textbf{r})$ and $\psi(\textbf{r})$...
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Collimated Beam through Palladium Powder to identify the lattice structure

I came across the following Problem: A collimated beam with a wavelength of $0.162 \ [nm]$ is incident upon a powdered sample of simple cubic metal palladium. Now, five angles are given, which ...
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Where is the gauge symmetry in an ideal Bose gas?

It seems in the literature that there is a certain notion of a “macroscopic wavefunction” associated with a Bose-Einstein system (see this PSE answer) which exhibits a global $U(1)$-phase symmetry. ...
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Is the work function a function? [closed]

The work function is the energy an electron needs to leave the metal. Why is it called a function? Its value is different for different metals, but that doesn't make it a function; density and melting ...
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Chemical potential in a simple semiconductor

I came across the following problem in my undegrad solid state physics book: Assume a semiconductor with two bands, the lower band is defined as $E(k)$ and the upper band is defined by $E_0 - E(k)$ ...
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Cesium chloride crystal structure

Cesium chloride has a cubic structure with eight $Cs$ atoms at each corner of each cube and one $Cl$ in the middle of the cube. It is stated in my solid state book that this crystal cannot be ...
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FCC and BCC lattice

Some crystals can be described by a FCC lattice or BCC lattice. For example diamond can be described as a FCC lattice with two basis vectors. Is it also possible to describe it using an ordinary cube ...
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Semiconductors/insulators: Why is the fermi energy between the valence and conduction band?

Ive asking myself a question on the fermi-energy. The fermi-energy is defined as the maximum energy which an electron, following the Pauli-rule, can have at T=0. In semiconductors and insulators the ...
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Can two atoms be a crystal?

In the physics literature, you can often find the term "two-ion crystal", when talking about two ions that are confined in a e.g. Paul trap. How is this possible? Shouldn't a crystal be a structure ...
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what is the electrical conductivity tensor for AC magnetic field and DC electric field in a metal?

I need to define electrical conductivity anisotropic tensor in a metal caused by Hall effect. My problem is that i don't know how to define it in case of oscillating magnetic field and static electric ...
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Interpretation of tilted energy dispersion cones in a Dirac Semimetal

The energy dispersion of a Dirac semimetal with an effective Dirac Hamiltonian of the form $$H=v_x \sigma_xk_x+v_y\sigma_yk_y+v_t\sigma_0k_y$$ is tilted in the y direction and the tilting increases ...
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Does the cold affect electrical conduction?

Disclaimer: I'm not experienced in many phyiscal nor electrical terms and I have no idea where to ask this question elsewhere. I'd be open for a move request if needed. Today when using public ...
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Exchange stiffness for HCP

I am studying the exchange interaction, which can be described with the Heisenberg Hamiltonian: $\hat{H} = -\sum_{i,j}J_{ij}\hat{\mathbf{S_i}}\cdot \hat{\mathbf{S_j}}$ In the framework of constant ...
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Electronic band structure of proteins

Proteins are a class of macromolecules. What range of electronic band structure do These have? Are These more like semiconductors? Or like insulators? How high is the typical Fermi Level for Proteins? ...
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Group velocity in different dimensions

I am given the following equation for the group velocity in one-dimension: $$v_g = \frac{d\omega}{dk}.$$ In solid state physics one has $-\pi/a \leq k \leq \pi/a$ for a one-dimensional lattice with ...
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Speed of a transverse wave in a solid medium

Based on the analogy with sound waves, can we say that the speed of a transverse wave in a solid medium is, $$v = \sqrt {\frac {G}{\rho}}$$ Where, $G$ is the shear modulus of elasticity of the medium ...
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Effective theory of hierarchial fractional quantum hall state

In describing the effective field theory picture of the hierarchical fractional quantum Hall states in Tong's lecture notes, page 165 he gives the expression for filling fraction, quasi-particle ...