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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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Calculating the number of free electrons in the conducting band [on hold]

Struggling to do this question: Using the Fermi-Dirac Probability function, the number of free electrons in the conducting band of a solid intrinsic semiconductor at $300$ K with bandgap $E_g = 1.10$ ...
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How can I plot numerically density of states against energy for semi-Dirac materials? [on hold]

maybe its not good question for this forum but i need to ask it .so please don't mind my question is that how can i plot density of states against energy numerically for the given dispersion ...
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Preconditioning self-consistent iteration

Publication arXiv:0804.2583 describes a method for doing self-consistent iteration without having to diagonalize the Hamiltonian operator at every step. IX. PRECONDITIONING As already ...
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Berry connection in a solid

I am having troubles to understand an equation-sign for the Berry connection in a solid. The general formula reads \begin{equation} \vec{A}(\vec{R}) = \mathrm{i} \langle \Psi(\vec{R}) \, | \nabla_{\...
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Berry Curvature in a hexagonal lattice

I am having troubles to understand the concept of the Berry curvature in a hexagonal lattice. What I know is: The Berry curvature $\Omega_n (\vec{k})$ for the $n$-th band reads \begin{equation} \...
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Creating a spatial variation of phase in a given superconducting sample

Blundell's book on Magnetism, talks about the generalized rigidities as a general consequence of spontaneously broken symmetries. In this context, it mentions that in a superconductor the phase of the ...
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Schottky anomaly in the heat capacity $C_{V}(T)$ of a 2-level system

Why does the Schottky anomaly in the heat capacity ($C_{V}(T)$ against $T$) associated with a 2-level system with energy spacing $E$ appear at $k_{B}T\approx\frac{E}{2}$ (a precise calculation gives $...
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Identify reasons for laser intensity fluctuation

I got a Mitsubishi LPC-826 laser diode (single mode) with laser driver iC-HG. There is no cooling device, but data was captured after 30 mins switching on (which should be temporally stable). The beam ...
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Role of d-band in metals

I have seen that in many publications authors discuss the metals in the d-block of the periodic table (often called 'transition metals') separately from other metals (e.g. alkali metals and aluminum). ...
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What is prerequisite for learning electrical transportation in material science? [closed]

I am doing my master's thesis, i already know Quantum mechanics, solid state physics, still studying Thermoelectric properties of nano material. I'm curious to know on what topic i can work in and ...
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1answer
47 views

Localization of $4f$ in rare earth and $3d$ electrons in transition metals

Is there a justification for why are the $4f$ electrons strongly localized about the nucleus in rare-earth atoms but the $3d$ electrons in transition metals extend further out from the nucleus? I have ...
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What is the difference between the differents lennard-jones parameters

I know different lennard jones potentials 12-6, 9-6, 9-3. I think the difference between them is the way they describe long-range interactions,but when I use each of them? Thank you in advance
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Optical axis of crystals

Can the optical axis of a double refracting crystal change?If yes,then what processes could be responsible for bringing about such a change?
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Steinhardt order parameter and radial distribution function

Is there a relation between the probability distribution of Steinhardt order parameter for BCC and FCC and their radial distribution function? In the picture we see the probability distributions of ...
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1answer
45 views

Why is a structure with holes and gaps stronger than a completely solid counterpart?

I often see abstract material designs like this http://news.mit.edu/2017/3-d-graphene-strongest-lightest-materials-0106 Why are such abstract shapes stronger than just a completely solid cube/...
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Can anyone recommend a book on sigma phase?

I am looking for a book in Solid State Physics where I could find a systematic approach to sigma-phase (closed packed structures) and high-entropy alloys. So far, I have only found published papers on ...
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1answer
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Conventional unit cells and Bravais lattices

Conventional unit cell is defined in the following: A definition of a conventional unit cell of a lattice is one that contains the same point group symmetries as the overall lattice and is the ...
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1answer
23 views

Localized and extended states in Landau levels due to disorder in Integer Quantum Hall Effect

In the presence of a random potential due to the presence of disorder, the degenerate Landau levels split into a band. It is given that the states in the middle of this band are extended and the ones ...
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Wave Function of the Tight Binding Model

The Gutzwiller wavefunction, i talked in brief in this other question, is introduced to compute the expectation value of the Hubbard Hamiltonian. It is composed by a uncorrelated Slater determinant (...
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Why luminescence peak can move to higher energies with increasing temperature?

Can somebody explain me, why sometimes I see changes in position of luminescence maximum as temperature dependence in dielectric crystals? Is this is caused by band gap changes or maybe some exciton ...
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Why is my measured LED activation voltage lower than theoretical?

I have done an experiment to measure Planck's constant. I measured the activation voltage of the LED for each wavelength used. I calculated theoretical activation voltage results using the energy of ...
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Plot function of kondo resonance model specific heat

I've been trying to plot the expression for the specific heat, as derived here. The function is $$ C/T= \frac{\Delta}{\pi T^2}-\frac{2 k_\mathrm{B}}{T} Re \Bigg(\frac{\Delta+i g \mu_B H}{\left( 2\pi ...
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What is the reason why at low temperatures the electromagnetic interaction becomes short ranged?

We know that at very low temperatures, the electrons start forming Cooper pairs and generate some sort of eddy current, so that a magnetic flux that is trying to penetrate the low-temperature object ...
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3answers
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How to show that the electrons responsible for a current have an energy within $k_BT$ of the Fermi energy?

It is commonly written in textbooks that in metals the electrons responsible for an electric current are the ones that have an energy about $E_F$ and a few $k_BT$ around that energy. See for example ...
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Lowest free energy 3rd Brillouin zone hexagonal structure

Consider a two-dimensional hexagonal lattice with the lattice parameter $a$ as shown in the figure. Question: What is the lowest free electron energy in the 3rd Brillouin zone? Attempted solution: ...
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1answer
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Why does diamond's specific heat capacity deviate from the Dulong-Petit theory at room temperatures? [closed]

Why does diamond deviate from the prediction of $c_v = 3k_B$ at room temperature more than other solids. Why do we require Debye's theory instead?
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How many atoms are in the primitive unit cell for diamond?

The primitive unit cell for diamond is pictured (the parallelepiped inside the cube). How many atoms are in the unit cell? My first guess is 3.5 and i know this must be wrong as the number of atoms in ...
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Viscoplastic Anand Model of Solder Alloy

I have found some data of viscoplastic Anand model for the SAC305 solder joint of electronic devices in the literature. Does this data depend on the thickness, length and width of the joint? I mean ...
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1answer
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why is X-ray photoelectron spectroscopy only for core levels?

I'm not sure why we can't get information from an atom, by looking at emitted electrons from the valence level. My book writes it is mainly a tool only for deep core levels. Why can't we use ...
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What is the lattice vector description of diamonds structure for a conventional fcc unit cell?

I understand how diamond has a conventional fcc unit cell with 4 extra atoms in it's basis. I also know that we can construct a primitive lattice cell using the lattice vectors: $\pmatrix{\frac{1}{2} ...
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2answers
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Solids are crystalline or amorphous. Where do polymers fit in?

Traditionally, solids are classified as being either crystalline (well-ordered, periodic lattice structure at large spatial scales) or amorphous (disordered structure). A well-ordered polymer is a ...
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What would be the Creep Response by using Boltzmann superposiition at t>t2

For detail see attach picture.. Under stress is σ, the creep response is given by , use Boltzmann superposition to estimate its creep response at t>t2 after the following stress history. [![enter ...
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Pulling apart the atoms of a topological insulator

Consider a topological insulator. In order to destroy a topological phase, the band gap of the bulk system should close at some point (passing thru a conducting state), but if the atoms that make up ...
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Why there is no reabsorption in LED crystals?

Can you explain to me please, why there is no reabsorption in crystals which are used as LEDs? Because the energy of emitted light is the same as the band gap of the semiconductor - it should be ...
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Band theory and molten metals

In solid state physics, features of crystals are explained by using the concept of energy bands, the existence of which is shown to be a result of the periodic order of the atoms in a crystal. When ...
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Why we consider excitations only near the Fermi surface?

In a metallic system, one typically consider states only near the Fermi surface. When we consider thermal excitation, I can understand this "approximation", because the Fermi-Dirac statistics implies ...
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How does approximations to assumptions lead to approximations to solutions?

I was reading Physics SE 228313. It talks about using Born-von Karman condition to model metal lattices. Is there any mathematical justification that approximations to physical condition would give ...
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Why can a nitrogen-vacancy center be viewed as a basic unit of a quantum computer?

I was on the Wikipedia page for Nitrogen-Vacancy Center and in the first paragraph the following statement is made: An individual N-V center can be viewed as a basic unit of a quantum computer, and ...
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2answers
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Hydrogen: Whether it's a metal or non-metal

I know hydrogen is a non metal, but when I just study about some introductory elementary band theory I find the band structure of hydrogen has a half filled valence band just like alkali metals, and ...
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Physical Interpretation of Energy-wavenumber Graphs

Consider an energy-wavenumber graph, typical in solid state physics, like the one below. I can follow the mathematics in the derivations with a KP model. But I don't understand the physical ...
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Why is the Peltier / Seebeck Effect's efficiency so low in practical devices?

Usually solid state devices are able to attain excellent efficiency. However, currently existing Peltier coolers and Seebeck generators have horrible efficiency -- far worse than Carnot, and also far ...
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Solid to Solid Vs Liquid to Solid Phase Transition [duplicate]

If we want to achieve Solid phase transition(means a solid transfer to another solid) and Liquid phase transition(means transformation of liquid into solid like water turned into ice..) then which one ...
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Band formation in diamond

Why is it that in the band diagram of diamond does the sp3 hybridised orbital split into two forming valence band and conduction band? I thought that these sp3 hybridised orbital forms 4n bonding and ...
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Are quasi-particles really particles?

In my understanding, quasi-particles were just some real world particle (like electrons) but in different environment i.e. an electron in a crystal. But Recently, I have started studying Spintronics/...
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For the high-frequency permittivity of a material, do I need to look beyond its value in the optical energies region?

I was trying to find $\varepsilon_\infty$ for InSb, and the value I found on Kittel p. 416 was 15.6. But in the literature, even at 6 eV, $\varepsilon (\omega )$ is still in the negative (at -3.835) ...
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How to derive equation (N.15) in Ashcroft and Mermin's Solid State Physics?

They state in their book on page 792 the following: It can be proved, however, that if $A$ and $B$ are operators linear in the $u(R)$ and $P(R)$ of a harmonic crystal, then: $$\langle e^A e^B \...
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Stress- Strain curve [closed]

Point A shows proportional limit, B shows Elastic limit, C shows UTS point, D shows Fracture stress(https://i.stack.imgur.com/7ep6j.jpg) So ive read that stress is basically the result of strain ...
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What are the differences between a slow moving and fast moving blade cutting through a material?

Examples could be an axe cutting through a wooden branch, a kitchen knife cutting through a carrot or a hydraulic sheer cutting through steel. Specifically I would like to know: Will the energy ...
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Hubbard model in magnetic field

Let's assume I have a Hubbard hamiltonian in a magnetic field. $H=-t\sum_{j,\sigma}c_{j,\sigma}^\dagger c_{j+1,\sigma}+c_{j+1,\sigma}^\dagger c_{j,\sigma}+U\sum_j n_j,_\uparrow n_j,_\downarrow +\...
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Symmetric BCS state

The ground state wavefunction for the BCS can be written $$|\Psi_{G}\rangle\equiv\prod_{\textbf{k}}[u_{k}+v_{k}c_{\textbf{k}1}^{+}c_{\textbf{-k}-1}^{+}]|\phi_{0}\rangle,$$ where $|\phi\rangle$ denotes ...