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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What is the state of matter of a (solid) yogurt?
Maybe this is a silly question, but I'm not quite sure.
Consider a solid yogurt. Can we assign a specific state of matter to it?
I mean, it behaves like solid. However, if we "mix" it with a spoon, ...
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1answer
62 views
Estimate the difference between two sets of atoms
I've been working on amorphous structures derived from a crystalline one (using MD) containing $N$ atoms. I want to prove that these structures are different and to quantify their "differentness". One ...
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2answers
102 views
Eigenfunctions in periodic potential
For Hamiltonian $\operatorname H$ and lattice translation operator $\operatorname T$, if
$$\operatorname H\psi=E\psi, \qquad \operatorname T\psi=e^{ik\cdot R}\psi,$$
and
$$\operatorname ...
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Why does silicon have an indirect gap?
Is there an intuitive explanation as to why silicon has an indirect gap? I have heard that this can explained using pseudopotentials.
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139 views
The definition of Density of States
The density of states (DOS) is generally defined as $D(E)=\frac{d\Omega(E)}{dE}$, where $\Omega(E)$ is the number of states. But why DOS can also be defined using delta function, as
...
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81 views
From the local Hooke's law to the global one
My system consist of a cylinder with axis Z that can contract and dilate along this axis. It obeys microscopically Hooke's law of elasticity:
...
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118 views
Reciprocal lattice and phonon
As we obtain a reciprocal lattice for a given crystal we see that discrete values of wavevectors are allowed but a phonon wavevector spectrum is a continuum. Is there a relation between reciprocal ...
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2answers
269 views
Why is there a Global Minimum for the Morse Potential?
For Diatomic molecules, the Morse potential describes their potential energy as a function of separation distance between the two particles.
My question is, what is the explanation of of the dip ...
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1answer
136 views
Supplements for Kittel's Solid State Physics? [duplicate]
I think by supplement I really mean replace. I spent a lot of time agonizing over the first chapter of Kittel as he introduces a bunch of concepts such as Bravais lattice and he doesn't clearly define ...
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111 views
Phonon Momentum
I am reading Charles Kittel's solid state physics and wondering what's the mechanism that neutron waves and photons can interact with phonons and the process obey the generalized momentum-energy ...
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2answers
75 views
What are some ways of inducing spin polarization?
I saw a talk today and they mentioned how nitrogen-vacancy diamond centers can be used to optically induce spin polarization and now I wonder what other ways there are to induce a spin polarization.
...
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1answer
122 views
Semi-conductor band-gap and deformation potential
Submitting a semi-conductor to stress leads to a deformation in the energy-bands, roughly described by:$$H_{ij} = {\cal{D}}_{ij}^{\alpha\beta}\;\epsilon_{\alpha\beta}$$
$\epsilon$ being the strain ...
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71 views
How to find the translation vectors of a primitive cell when primitive cell encloses multiple atoms? [closed]
How to find the translation vectors of a primitive cell when primitive cell encloses multiple atoms?
Your help is appreciated!
Thank you!
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96 views
Dispersion relation in continuum mechanics
I'm looking at the vibration of a solid having a lattice structure, they obey the following equation:
$$\rho\partial_t^2u_i = C_{ijkl}\nabla_j\nabla_ku_{l}$$
with $u(\vec{x},t)$ the displacement to ...
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33 views
Residual symmetries of the superposition of two fcc lattices
Fcc lattices are Bravais lattices and so are invariant under a set of discrete translations plus inversions over the 3 axis ($x\rightarrow -x$,$y\rightarrow -y$,$z\rightarrow -z$). When one superposes ...
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235 views
Ashcroft Mermin Solid State Physics Eq. 2.60ff
I'm trying to follow the steps in Eq. 2.60 of said book.
What I cant seem to figure out is how to change the integration variables from 'k' to 'E', as they state.
The equation is
$$\int ...
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186 views
Learning roadmap for solid state physics [duplicate]
I am a PhD student in mathematics who knows little more about physics than what one learns in high school. For my research on tilings of space and aperiodic order, every now and then I have to skim a ...
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229 views
Crystal visualization software for visualizing lattice with reciprocal vectors drawn in same image [closed]
I'm looking for a free crystal visualization program, preferably for Linux, that can visualize the common lattice structures in 3D interactively (rotatable with mouse) and draw in the same picture the ...
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Rice Allnatt distribution function
Can anyone give me an article of which explains Rice Allnatt distribution function or can you explain the function here?
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220 views
In the diode equation, why the exponential $\exp$ and the ideality factor $n$ are there? What do they represent & what is their significance?
In the Shockley diode equation, why the exponential $\exp$ and the ideality factor $n$ are there? What do they represent & what is their significance?
I have to work on Solar Photovoltaics, and ...
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61 views
Where to learn Temperature Dependent Conductivity induced by Electron-Phonon Interaction? [closed]
I want to learn how to calculate the temperature dependent conductivity induced by electron-phonon interaction.
I know in low temperature, the resistance in metal $\rho$ is proportional to $T^5$, $T$ ...
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1answer
610 views
Effective Mass and Fermi Velocity of Electrons in Graphene:
In graphene, we have (in the low energy limit) the linear energy-momentum dispersion relation: $E=\hbar v_{\rm{F}}|k|$. This expression arises from a tight-binding model, in fact $E =\frac{3\hbar ...
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202 views
How to determine real part of optical conductivity by reflectivity measurements?
In figure 3 of this document, there is data relating $\Re(\sigma(\omega))$ to the Fermi energy. It is claimed that $\Re(\sigma(\omega))$ is determined via reflectivity measurements. How is this done? ...
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How were the crystal lattices of elements determined to perfection ? (Ex:- That of a copper is a cubic lattice ) [duplicate]
Possible Duplicate:
How can crystal structures be determined using X-ray diffraction?
Are there any simple means in order to verify the nature of complex lattices like that of Triclinic , ...
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1answer
145 views
Energy spectrum of a tight-binding model
Consider the one-dimensional tight-binding Hamiltonian
$$\mathcal{H}=t\sum_m\left(a^\dagger_m a_{m+1}+a^\dagger_{m+1} a_{m}\right).$$
With the lattice constant set to 1, the energy spectrum is given ...
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Crystal momentum and the vector potential
I noticed that the Aharonov–Bohm effect describes a phase factor given by $e^{\frac{i}{\hbar}\int_{\partial\gamma}q A_\mu dx^\mu}$. I also recognize that electrons in a periodic potential gain a phase ...
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232 views
Mobility in semiconductors
Good afternoon everybody.
I am reading on a book about semiconductor mobility. I have fully understood the definition, but I also noticed that often one talks about high or low mobility. My question ...
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119 views
Why is a critical system equal to a gapless system?
In condensed matter physics, people often say that a system without energy gap is a critical system. What does it mean?
Any help is appreciated!
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141 views
Why is diamond structure the most stable structure? [closed]
Why is diamond structure the most stable structure? Is this mathematical issue or physics issue?
Doesn't this relate to quantum physics?
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1answer
382 views
Resistance between two points in an infinite metal sphere/cube
Let's imagine that we have a tridimensional metal object of infinite size, and decide to calculate the resistance between two arbitrary points. How would we go about doing this?
I have thought of two ...
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216 views
Does a quantum phase transition have latent heat?
As the title says, I am thinking about the question that whether a quantum phase transition has latent heat. If so, at 0 temperature, we can drive the system by some parameter from disorder phase to ...
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1answer
81 views
How creation of point defects in semiconductors is affected by strain?
When the effect of the strain on solids is discussed, normally the explanation is the following: increasing stress, first point defects created, then dislocations, then plastic deformation starts, ...
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2answers
966 views
How can crystal structures be determined using X-ray diffraction?
You have the intensity peaks and the diffraction angles. Let's say you suspect the material is cubic, how do I find if it's simple cubic or BCC or FCC?
I've googled and all my textbooks just state ...
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386 views
What is the difference between a photon and a phonon?
More specifically, how does a wave-particle duality differ from a quasiparticle/collective excitation?
What makes a photon a gauge boson and a phonon a Nambu–Goldstone boson?
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356 views
Relation between density and refractive index of medium
Is there any relation between Refractive index and density of a material? It is not found to be proportional in my experimental results. Is there any equation to relate these parameters?
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53 views
Charge carrier injection in heterostructures - help with concept definition
I have this report to do on "Charge injection in heterostructures". I have been searching and reading but I still have some trouble with the basics, i.e. defining the concept.
As far as I understood ...
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208 views
Simulating the evolution of a wavepacket through a crystal lattice
I am interested simulating the evolution of an electronic wave packet through a crystal lattice which does not exhibit perfect translational symmetry. Specifically, in the Hamiltonian below, the ...
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55 views
Cubic symmetry and a stiffness tensor [duplicate]
Possible Duplicate:
Stiffness tensor
Let's have a stiffness tensor:
$$
a^{ijkl}: a^{ijkl} = a^{jikl} = a^{klij} = a^{ijlk}.
$$
It has a 21 independent components for an anisotropic body. ...
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51 views
Finding out the wavelength of Xray [closed]
A sheet of aluminum 1 mm thick reduces the intensity of a monochromatic x ray beam to 23.9% of at original value. what is the wave length of xray.
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239 views
Lagrangian of 2D square lattice of point masses connected by springs
Zee's QFT book mentions the Lagrangian of a square 2D horizontal lattice of point masses, connected by springs, and considering only vertical displacements $q_{i}$, as
$ L = \frac{1}{2} ...
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99 views
Ways to experimentally control the chemical potential of a solid state system
When working in the grand canonical ensemble we write the grand potential as $\Omega = \Omega (T,V,\mu)$. In this case we are taking the chemical potential $\mu$ to be an independent variable. This ...
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What is Z3 exciton?
I am searching and studying excitons and I confronted with a term named Z3 exciton. What is it? And what is its difference with, for instance Z1 or Z2 exciton?
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Characteristics of bloch electron in a priodic potential
Effective mass of a Bloch electron in a periodic potential is negative why ?
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52 views
Order of magnetic phase transitions
Is there any phase transition occur in paramagnetism to diamagnetism transitions state. What should be the order and how will I calculate the order?
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113 views
Phase diagram problem for ternary system
For a ternary system, three composites are present.
Temperature is also a variable.
Assuming that pressure is held constant, what is the minimum number of phases that may be present in a ternary ...
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111 views
Stiffness tensor
Let's have a stiffness tensor:
$$
a^{ijkl}: a^{ijkl} = a^{jikl} = a^{klij} = a^{ijlk}.
$$
It has a 21 independent components for an anisotropic body.
How does body symmetry (cubic, hexagonal ...
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3answers
339 views
Derivation of the “Bethe sum rule”
I am trying to work out the steps of the proof of the expression: $$\sum_n (\mathcal{E_n}-\mathcal{E_s})|\langle n|e^{i\mathbf{q}\cdot\mathbf{r}}|s \rangle|^2 = \frac{\hbar^2q^2}{2m}$$ from Eq. (5.48) ...
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201 views
Simple model of edge states for a two-dimensional topological insulator
Quantum spin Hall states or, topological insulators are novel states of matter that have insulating bulk and gapless edge states. Are there any simple models that show these features?
See e.g. the ...
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198 views
What is different between resolvent and green function
I bumped into a book, where Resolvent $R^{\pm}(E)$ is defined as
$e^{\mp iHt/\hbar}=\pm\frac{i}{2\pi}\int_{-\infty}^{\infty}dER^{\pm}(E)e^{\mp iEt/\hbar}$
and
$R^{\pm}(E)=\frac{1}{\pm ...
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Why do the drift and diffusion components cancel for each type of carrier if EHP generation plays such big role in p-n-junctions?
I have always argued to myself that drift and diffusion components of the current though a p-n-junction cancel for each type of carrier because any electron diffusing from n into p will sooner or ...
