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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Young's Modulus and Shear Modulus relationship

Suppose a 3D simple cubic crystal in which nearest-neighbor atoms are bound by springs with equilibrium length = lattice constant $a$ and spring constant $C$. How can I find Young's modulus $C_{11}$, ...
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Energy levels of atoms

It is said when atoms bond together to become molecule their energy levels merge and split, resulting in splitting of spectral lines in molecular spectra. Why? Plz explain in layman term
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MOSFET current at very low temperature (4K)

I am trying to model the current at low T. To do so I need to compute the integral of fermi dirac statistics multiplied by the conductivity, with respect to energy: My problem is that I cannot ...
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About the “freedom” in the conduction band

Because atoms in a material are close together, electron wave function from different atoms interact, and they couple. But as Pauli exclusion says, two electrons cannot have the same quantum state, ...
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Zener effect - how does the probability of tunnelling increase under an increasing potential barrier?

From Wikipedia (the basis of my lectures): Under a high reverse-bias voltage, the p-n junction's depletion region widens which leads to a high-strength electric field across the junction. ...
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Can (anti)ferromagnet be superconductor by proximity effect?

If I put a very thin (anti)ferromagnet between two superconductors, is it possible to become a superconductor via proximity effect? For example, a supercurrent exists with zero voltage drop.
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How to calculate the magnetic flux density between the two permanent magnets ( Ring type)? [closed]

Outer Diameter - 90mm Inner Diameter - 50mm Distance between the two magnets - 10mm Thickness - 15mm
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How does too much current 'kill' a type-2 superconductor?

I recently saw this post: Can a superconducting wire conduct unlimited current? One of the responses mentioned the Meissner effect. However, I am aware that this occurs primarily in type-1 ...
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23 views

Entropy of Mixing Derivation

In Thermodynamics and an Introduction to Thermostatistics 2nd Edition, Callen states that the Entropy of a mixture of ideal gases is given by (3.39) $$S = \sum_j N_js_{j0} + \left(\sum_j N_jc_j\right)...
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A doubt with respect to equilibrium in heterogeneous system

This is particularly with regard to "Equilibrium in heterogeneous systems",it is given that he stable phase forms of pure A and ppure B at a given temperature and pressure can be denoted as $...
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Estimating Debye and Fermi temperatures

Given the sketch of the behavior of the heat capacity against the temperature, How do I estimate the Debye and Fermi temperatures? Thank you in advance
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Hamiltonian that contains only one-particle operators are always solvable

Consider a Hamiltonian for an N-body system that has only single-particle operators. $$ H = \sum_{i,j} h_{ij} a_i^\dagger a_j $$ with $h_{ij}=\langle i |H|j\rangle$, and $a_i^\dagger (a_i)$ create (...
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Derivation of the current density for the free electron gas

I have a few doubts about the study of the free electron gas model: We know that the current density expression may be calculated as follows J(r,t)=$\frac{\hbar}{2mi}(\psi^{*}\nabla\psi -\psi\nabla\...
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Is there any spin-resolved time-resolved ARPES?

Has the technique of both spin- and time-resolved ARPES been realized and applied anywhere?
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The contradiction of the equation of motion of a free electron

I've been confused of the equation of motion of a free electron inside a conductor as a current flows. $\mathbf{v}:=$average velocity of free electrons inside the conductor. $\tau:=$relaxation time. $...
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Electron heat capacity vs phonon heat capacity

For metals, the heat capacity has two contributions. The phonon contribution is proportional to $T^3$, while the electron contribution is proportional to $T$, as $T$ goes to zero. Therefore, for ...
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Change of semiconductor

Si is a very known semiconductor. I was wondering how changes in the period of the same group affect the energy of the different energy bands.So for an example if go to Ge from Si(3rd period from 2nd ...
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Closed formula for neighbors in FCC lattice

I wonder if there is a close formula for the sequence of distances of neighbor shells in an FCC lattice, i.e. a formula of the form $d_n = a f(n)$ where $a = \frac{A}{\sqrt{2}}$ is the nearest-...
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Relation between many-body system's single-particle retarded Green' function and Propagator for single particle wavefunction

In the 8th Chapter of book Many-body Quantum Theory in Condensed Matter Physics by Henrik Bruus and Karsten Flensberg, they give an explicit form of retarded Green's function (GF) for the many-body ...
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Finding the K-Path of High Symmetry Points in the Brillouin Zone

I am trying to understand how to find the K-Path of high symmetry points in the 1st Brillouin Zone. Can someone explain to me what does $\Gamma-X-U \space|\space K-\Gamma-L-W-X $ mean for the case of ...
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BCS Theory incomplete [closed]

Hi I am currently studing the BCS theory and I am wondering if I shouldnt study it because it is incomplete :it doesnt explain superconductivity at high temperatures.Is there an ongoing research to ...
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Plotting a bandstructure along high-symmetry paths in the Brillouin Zone

I am trying to finalize my band structure plot for twisted bilayer graphene. I have been having some problems with the plot itself. To troubleshoot my code, I first just looked at the diagonal part of ...
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Hall effect vs GMR

I am studying about GMR(Giant Magnetoresistance) and I am wondering:Since both the Hall effect and GMR produce change in resistance of the wire how can scientist know it isn't the Hall effect from 2 ...
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1answer
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Linear chain Hamiltonian [closed]

In Ziman's Electrons and Phonons book, he starts describing phonons with a linear chain. On Page 7, Eq. 1.3.6, he gives the potential energy as $$ V = \frac{1}{2}g\sum_l{(n_{l+1}-n_l)^2} $$ where $g$ ...
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Bravais lattice point groups

I'm trying to describe Bravais lattice point groups as permutations of lattice points. In doing so, I encounter a problem: I can only find descriptions of Bravais lattice point groups in terms of ...
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Grow Synthetic Crystals at home with Induction Heater [closed]

Using an induction coil with a graphite crucible is it possible to grow synthetic crystals at home with this setup? I know that the setup would have to include some precise control of vertical draw (...
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Angular dependence of Moiré-pattern arising in twisted graphene bilayer

My question is, if there is any known expression for the angular dependence of Moiré-pattern formation in twisted hexagonal bilayers. The most well-known example for the occurance of the Moiré-effect ...
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Does Spin-Orbital Coupling (SOC) have no effects on orbitals with different $l$?

SOC term is: $$H_{\mathrm{SOC}}=\alpha \vec{L} \cdot \vec{S}=\frac{\alpha}{2}\left(L^{+} \sigma^{+}+L^{-} \sigma^{-}+L^{z} \sigma^{z}\right)$$ from spin Orbital Coupling matrix in p-orbital basis, we ...
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In an intrinsic semiconductor, are there the same number of carrier electrons and holes? Or this is just exclusive for silicon?

I am working with some polymers that behave like semiconductors when they are plugged into the current. I am calculating the mobility of these polymers and I need the value of the current density (J) ...
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1answer
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Physical meaning of the real part of the conductivity as a function of frequency for a time-dependent electric field

I apologize if this question has been asked before. My Solid State professor was explaining the Drude model, and what happens to a solid when we apply a time-dependent electric field. In a lecture, we ...
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Does changing the wavevector $k$ of an electron in a band mean the same as changing its wavelength?

If crystal momentum is transferred by a phonon to an electron with wavenumber $k$, i.e. the electron has then the wavenumber $k^\prime$, does this also change the electrons wavelength $\lambda$? Is ...
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Does doping affect the number of band states?

Does doping a semiconductor with acceptor impurities affect the number of states in the valence and conduction bands? How about doping with donor impurities? It seems to me, that in the former case ...
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Writing Basis for the unit cell

I'm following The oxford solid state basics By S. Simon. I'm sort of confused, How he has written the basis in different places? The definition that is given goes like this: The description of ...
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What is the Lattice Constant?

What is a physical description of the lattice constant and how does one calculate it? From what little resources I have found, I have figured out that it has to do with the size of the atoms that ...
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Is there a place online to look for lattice structures and constants for most (if not all) of the crystals constituted of single element?

For example, if I want to look for lattice structure and constants (unit cell side lengths, angles) of the Bismuth crystal, where should I go for? It is more important for me to know the cell ...
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Intrinsic carrier concentration in doped semiconductors

For an intrinsic semiconductor, due to thermal energy we get some carriers whose concentration is known as intrinsic carrier concentration. Now if we dope the material we'll have carriers both due to ...
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Time reversal of scalar Bloch states

There's a well-known result about time reversal symmetry in crystals that's important when studying the physics of topological insulators, but I am having trouble proving it. I'll start with notation. ...
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Finding the number of particles per unit area along a given plane

We are given a problem in our class that goes like this: In a simple cubic lattice constant $0.287$ nm, the number of atoms per $\text{mm}^2$ along the plane $111$ is $2.11\times 10^{13}$ $1.73\...
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24 views

Number of electron-hole pairs produced by each photon in depleted silicon

What is the distribution of the number of electron-hole pairs produced by a single photon in depleted silicon? Can you point me to bibliography on this? I am currently interested in 1064 nm photons ...
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Which one is the correct representation of the Landau levels?

Sometimes the Landau levels in a finite 2D sample drawn as in the figure below: where the energy $E$ is graphed against the width $x$ of the sample in real space where $x=0$ and $x=W$ are the two ...
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Does zero chemical potential implies zero lowest energy level for non-interacting quasiparticle excitations?

Many of the quasiparticle excitations in solids have non-conservative particle numbers. Examples are phonons, magnons, excitons etc. Therefore, as many posts put, the chemical potential should be zero....
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Density of an electron gas in 3D using surface integral

I am trying to derivative the state density using the method I mention in my title. This is how I begin : $$V/(2\pi)^3 \cdot \int_0^EdS_k/|\nabla_kE(k)|.$$ I use spherical coordinates to express the ...
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Are there substances that behave as perfect conductors but not superconductors?

Does there exist substances which below a certain temperature becomes as a perfect conductor but not a superconductor? A superconductor is both a perfect conductor as well as a perfect diamagnet. If ...
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The equilibrium filling factor for the Landau levels in graphene

According to the expression of the coefficient (alpha) which is at the bottom, i do not konwn the exacte expansion or value of the equilibrium filling factor for the Landau levels in graphene (rau n, ...
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Why exactly do bonds form?

From my solid state physics class I know about all the various types of bonds and the mechanisms that cause them. Let's leave the specific physics aside for now and just accept that a bond lowers the ...
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How to calculate the overall entropy when continuous 2D positions are known?

If I have the positions of particles in continuous 2D space, how do I calculate the entropy of the system? The particles are invariant, I just need some measure of how organised they are, but I'm not ...
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Does Bohr van Leeuwen theorem not exclude the possibility of explaining paramagnetism classically?

We have the Bohr-van Leeuwen theorem which tells that magnetism cannot be explained classically. The proof is simple; it turns out that classically the partition function is independent of the ...
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Book on Solid State Physics [duplicate]

Which is the best book for Solid State Physics / Condensed Matter Physics, which uses quantum and statistical mechanics fluently and has nice practice problems?
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Would many extremely fine (solid) granules exhibit similar properties as a fluid? [duplicate]

A while ago this random thought crossed my mind: I am not even sure if the question is valid or makes sense, but I can sort of imagine a powder (consisting of of granules with a diameter way less than ...
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Charge carrier density for alloys

If we go to Aschcroft&Mermin we find formula for charge carrier density: $n=\frac{N_AZ\rho_m}{m_a}$ This formula is pretty simple and written in every solid state physics textbook. So my question ...

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