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 does the Equation $E_s = -dF$ mean in terms of a Rydberg Atoms Dipole Moment and its Energy?

Could someone explain what the equation $E_s = -d$•$F$: Where, '$d$' is the Rydberg Atoms Dipole Moment, '$F$' is The Electric Field Strength and '$E_s$' is the Energy of the Rydberg Atom. In terms ...
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31 views

How can I determine the convergence of self energy in Green's function

I want to solve for the Green's function (in the context of many body theory) but I have a question. After the determination of the retarded Green's function and the lesser Green's function we ...
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15 views

States in valence and conduction band

I often see a Hamiltonian in second quantization written for the valence and conduction band. Now, I was wondering: What are the single-electron states that form the prouct state they act on? So what ...
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14 views

Tight binding method -kittel [on hold]

Actually my study on tight binding method from Solid state physics- Kittel is in totall mess. There are couple of points I would like myself to clarify on -How $\boldsymbol{<\phi_{m}|\phi_{j}>}$ ...
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302 views
+250

Horrifying electron gas model

I am given the Hamiltonian, in an exercise called plasmons, and where $\langle, \rangle $ denotes the expectation value. $$ H = \sum_{k} \varepsilon_k a_k^{\dagger} a_k + \sum_{k_1,k_2,q} V_q ...
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+100

Coordinate system for crystallographic groups

In the International Tables for Crystallography for each crystallographic group an asymmetric unit is supplied (mathematicians call this a fundamental domain of the group). This region is a bounded ...
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46 views

Why are (most) solids periodic?

Is there a rigorous proof that periodic arrangements minimize the energy of a group of particles?
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1answer
58 views

Origin of High-temperature Superconductivity

What is the mechanism that causes certain materials to exhibit superconductivity at temperatures much higher than around 25 kelvin?
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18 views

Symmetry breaking and band gaps?

Can the discontinuity in the E-K dispersion relation of a periodic lattice (at the boundary of a Brillouin zone) be understood as a consequence of breaking continuous translation symmetry into ...
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709 views

How is potential energy (PE) actually stored in a steel spring at the atomic level?

Elasticity is one the most intriguing phenomena, wiki gives a summary explanation of what happens in a steel spring: the atomic lattice changes size and shape when forces are applied (energy is ...
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1answer
30 views

How do discretize a finite crystal?

I am trying to find a general method to discretize a finite crystal system. How I have been discretizing systems so far (using Wannier functions): When you have an infinite crystal, you may apply ...
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23 views

Why does Pressure Increase the Tc (Critical Temperature) of a Superconductor?

Just a heads up - please make this answer understandable to around 1st year degree level physics - not PhD research. So I can understand it - thanks. I was wondering why they Critical Temperature ...
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1answer
42 views

Why isn't doped silicon a strongly correlated electron system?

Most books on strongly correlated electrons claim that when the number of itinerant electrons is small and the screening length is large, that the system becomes "strongly correlated", (i.e. the ...
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Crystal in Magnetic Field

When you have a 2D crystal in a uniform perpendicular magnetic field, you can use the Peierls substitution to convert one tight-binding before-magnetic-field-band into a $q$-bands under the influence ...
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10 views

Binding forces in crystalline solids

I am referring to rocks in this instance. Individual crystals grow together in an igneous rock as it solidifies. I know that the SiO4 tetrahedron is the basic building unit of silicate minerals, and ...
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18 views

Coupling a ferromagnet to an antiferromagnet

Consider a system composed of a thin film of FM material on top of an AFM material. From my research I found that pinning of the FM material occurs when we cool the system from $T_N<T<T_C$ to ...
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32 views

The correspondence between real space and reciprocal space

From what I've learned, a point $P=(h\ k\ l)^T$ in the real space can be expressed as a linear combination of the primitive vectors $$A\left(\array{n_1\\n_2\\n_3}\right)=P$$ Where $A=(a_1a_2a_3)$ is ...
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1answer
54 views

How does current flow in superconductors if Cooper pairs have zero momentum?

I've been reading a lot of condensed matter textbooks, which state both that the net momentum of a Cooper pair in a superconductor is zero, and that Cooper pairs have momentum when they carry current. ...
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22 views

intervalley optical phonon scattering

Is there any difference between intravalley and intervalley optical phonon scattering self-energies in NEGF method?(except that electron-phonon coupling constants)
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1answer
36 views

How corner atom of a cube is shared by 8 atoms? [closed]

Since each atom is at the corner of a cube and 8 cubes meet at each corner. Therefore each atom is shared by 8 cubes. But I don't visualize it, so please tell how I Visualize it.
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29 views

Hartree Fock exchange kernel

I would like to understand, how we calculate the exchange kernel of the Hartree Fock equations for a coulomb potential. So in slide 19 here for example you see the result, but I have not the ...
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1answer
80 views

How do I derive the eigenvalues of the 1D Heisenberg model? (Bethe Ansatz)

I've been trying to work through Introduction to the Bethe Ansatz I (by Michael Karbach and Gerhard Muller) in spare time and I am having trouble deriving the eigenvalues given in equation (5) for ...
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0answers
18 views

How does quantum confinement happen in amorphous or polycrystalline materials?

You can easily find papers where they make a nanostructure (thin film, nanowire, or quantum dot) from methods (ALD, CVD, thermal/egun evaporation) that produce amorphous or polycrystalline structures ...
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Real part of the AC conductivity has a discrete spectrum => What physics?

If the real part of the AC conductivity $\text{Re}[\sigma(\omega)]$ has a discrete spectrum only, i.e., $\text{Re}[\sigma(\omega)]=a_1\delta(\omega-\omega_1)+a_2\delta(\omega-\omega_2)+\cdots,$ what ...
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21 views

Crystallography and symmetry operations

I am trying to figure out the basis for deuterate solid state water. To do so I took the position of the basis atoms from http://rruff.geo.arizona.edu/AMS/amcsd.php and then I applied the symmetry ...
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37 views

Why don't electrons simply diffuse back when illuminating a photodiode?

Assuming you connect the cathode and the anode with a conductor (no sources), why can't the electron-hole pairs created by the photons diffuse back instead of going through the wire? My reasoning is ...
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25 views

Crystal lattices in solid state

I found this problem in Christman's book fundamental of solid state physics What is the Miller index for a plane parallel to both $3\vec{a}+\vec{c}$ and $\vec{b}$, in any lattice?
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Screened potential of charged impurity in a 2-dimentional electron gas

What's the analytical relation of screened potential of charged impurity in a 2-dimentional electron gas?
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46 views

Time reversal operator in tight-binding model with second quantization form

In tight binding model, $H=\sum_{r,r'}ta^{\dagger}_{r}a_{r'}+h.c.$.When now conducting a time reversal transformation, what form will this Hamiltonian like? Or how can I express time reversal ...
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1answer
40 views

Influence of applied voltage to an electron of a metal

I would like to ask what would happen to the potential well of an electron being trapped in a metal? If I apply a voltage trying to accelerate the electron out of the potential well. Would It make the ...
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1answer
27 views

Question about the derivation of tight-binding model in the form of second quantization

There is a step in such derivation that I cannot follow. That is eq(1.74) in http://www.itp.phys.ethz.ch/education/fs13/sst/Lecture-Notes.pdf in page 21. How does these non-crossing terms vanish? ...
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1answer
75 views

To what extent can the superconducting order parameter be thought of as a macroscopic wavefunction?

I know that the order parameter does not obey the Schrodinger equation; it instead obeys the Ginzburg-Landau equation. However, I am unclear as to the situations under which the view of the ...
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27 views

A model for surface adsorption

I have been trying to model the adsorption of an inert gas on the surface of a clean solid. So far my underlying goal is to express the Gibbs energy as a function of the number $N$ of adsorbed ...
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25 views

The Debye temperature for diamond

To simplify the calculation, let's assume that the average speed of sound in the diamond is simply $v_s=\sqrt{E/\rho}\simeq1.414\times10^4 \ \text{m/s}$, and the Debye frequency $$\omega_D=v_s\left( ...
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42 views

Folding of wave-vector in Band Theory of Metals

In the Kronig-Penney model in the Band Theory of Metals, we derive the energy levels as function of wave vector as shown in the figure. But my professor showed that we represent the levels folded ...
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31 views

Why do electrons form Cooper pairs below certain temperature? [duplicate]

Just a heads up - please make this answer understandable to around 1st year degree level physics - not PhD research. So I can understand it - thanks. 1) In solid state physics, why is it that below a ...
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0answers
25 views

Discrepancy in introducing Schottky barrier

I have a problem regarding introduction of Schottky barrier in metal-semiconductor junction. Because of this barrier the energies of conduction band vary discontinuously and hence the potential is ...
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69 views

The reciprocal lattice of HCP lattice

There is a very similar question here Reciprocal Lattice of a non-bravais lattice, but I don't fully understand the answer, and the question is now obsolete so I feel that I should ask it again. How ...
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1answer
34 views

Help needed to understand the dispersion curve of a 1D lattice with diatomic basis

I am trying to understand the dispersion curve (as shown below) of a 1D lattice with diatomic basis. Here are my questions: Can both optical and acoustic branch of phonon simultaneously exist in ...
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1answer
52 views

Wannier Hamiltonian in Momentum Space

In connection to a previous question, We can write the one-particle Hamiltonian in the Wannier basis working on a general vector $v$ as : $$ \langle\vec{R},\,\lambda|\hat{H}|v\rangle = ...
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1answer
63 views

Wannier Functions as Discrete Basis

In solid state physics, using Bloch's theorem we know that the one-electron energy eigen-function can be written as $\psi_{\lambda,\vec{k}}(\vec{r})$ where $\lambda$ indexes eigenvalues of $\hat{H}$ ...
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108 views

Why doesn't topological phase transition break any symmetry? Hidden symmetry?

This question may be superficial. However why all people saying this without a proof? Just like the "hidden variables" assumption in quantum mechanics, can one disproof that there is no hidden ...
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Real materials described by the fermionic Hubbard model?

I was always curios what real material are described by the fermionic Hubbard model. $$H = \sum_{\left< i, j\right> \sigma} t_{ij} c^{\dagger}_{i, \sigma} c_{j, \sigma} + \sum_i U_i ...
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How to compute matsubara frequency summation over computer?

Matsubara frequency sum usually takes the following form: $S_\eta = \frac{1}{\beta}\sum_{i\omega_n} g(i\omega_n).$ But in my problem, $g(i\omega_n)$ is a lengthy expression, which can not be ...
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Proton energy distribution after Si layer

I've been using SRIM to get an approximation of the energy distribution that a beam of monoenergetic incident ions will have after a thin layer of silicon. However, for my purposes it would be better ...
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1answer
45 views

How to understand the unitary? [closed]

In the page 219 of Mahan's Many Particle Physics(3ed), there exists a transform $$ S=c^{\dagger}c\sum_q\frac{M_q}{\omega_q}(a_q^{\dagger}-a_q)$$ In order to prove that the transformation relating to ...
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21 views

Lecture notes of many body theory of solids [duplicate]

Can anyone help me to get a complete and comprehensive lecture note of the "many body theory of solids" according to the book written by John C. Inkson, please?
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Hamiltonian governing liquid to a solid transition

What is the Hamiltonian 'H' (at the atomic or molecular level) that governs the phase transition from a liquid to a solid state? Actually, I want to explicitly verify the Hamiltonian 'H' admits the ...
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2answers
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What's the difference between hopping and tunneling?

My professor made a distinction between electron hopping (the closest wikipedia had an article on) and tunneling, saying that one (he didn't say which, but I assume hopping) was temperature dependent ...
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1answer
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A problem about solving energy bands by the method of second quantization

In hopping model, we can get the Hamitonian as $H_0=-t\sum a^\dagger_ia_{i'}$. Then we take the fourier transform and put the operator which are in momentum space in the Hamitonian above. However, I ...