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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Why doesn't matter collapse, if I can view it as being made of bosons (atoms/molecules)?
I have often heard it said that the Pauli exclusion principle is responsible for the existence/stability of bulk matter. Wikipedia makes such claims and quotes great physicists who made such claims. ...
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Trivial vs Non-Trivial Bandgap in Optics
Can someone please explain what is the meaning of trivial and non-trivial bandgap in the context of topological photonics? This term often comes in the papers with band structure images which I can't ...
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First order for current expanded in hybridization expansion
I am working with this issue, I want to find the order 1 current for a single impurity Anderson model in the hybridization expansion.The current can be written like
$$I_{\sigma,L}(t)=-2\Im[\text{Tr}(\...
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What is special of the transition metals?
The title of a book I am now reading is 'multiplets of transition-metal ions in crystals'.
I am curious about one point. Why transition-metal? What is the point of emphasizing it? It seems to me that ...
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Does Berry phase $2\pi n$ mean anything?
Today I tried computing the Berry phase for some time periodic system evolving under the Schrodinger equation, and got the following result - upon completing a period, the $n$th eigenstate will ...
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What is the meaning of the temperature dependence of the Hall coefficient?
I would like to know the physical meaning of investigating the temperature dependence of the Hall coefficient.
It is known that the Hall coefficient is used to investigate charge carriers in a ...
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Doesn't counting hole and electron current lead to double-counting of actual current?
Consider two adjacent silicon atoms in a crystal, where the right nuclei is actually a hole. An electron transfers from the one on the left to the right. If we were to count both hole current and ...
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Is the Luttinger liquid a limit of the Kitaev chain model?
From what I understand, they are both models of electrons on a nanowire, but the Hamiltonian is different, just in the pairing term. When I look up the connection between them, there's surprisingly ...
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Fermi level of oxide layer in MOS
At equilibrium, I know the Fermi level of metal needs to align with the Fermi level of semiconductor at equilibrium. But it is not clear to me whether the Fermi level of oxide layer needs to align ...
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What does it mean to break a Cooper pair?
I am studying BCS Theory for the first time, and I did encounter the Bogoliubov-Vitalin transformation for the BCS hamiltonian, that gives
$$
\hat{\mathcal{H}} = - \sum_\mathbf{k} \sqrt{\xi_\mathbf{k}^...
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Help with proving the von Roos kinetic energy operator is Hermitian
When calculating the kinetic energy of a variable mass quantum system, such as a semiconductor heterostructure where mass has spatial variance due to the effective mass approximation, von Roos (Phys ...
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Radiative or non-radiative emission
If a material absorbs photon, it's electron on outer valence band absorbs its energy and jumps to the higher energy level, when the band gap is similar to the photon's energy. If so, what determines ...
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Why only trap states near the intrinsic Fermi level are considered in the Shockley-Read-Hall recombination theory?
Most of the solid state device textbooks (UG level) that I went through considers trap states at the intrinsic Fermi energy while applying the Shockley-Read-Hall (SRH) theory. It is stated that these ...
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Does a cube under high pressure transform into a ball?
Will a material in the shape of a cube, under high pressure, crumble into the shape of a ball?
One would expect that there will develop strains and stresses, after which the corners crumble and ...
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Non-trivial "energy coverings" of reciprocal space
My question is about sheets of the Fermi surface and their mathematical properties.
As far as I understand, in the one-electron approximation with a weak periodic potential (Bloch approximation) you ...
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Bending of vacuum level in pn junction
The vacuum energy level is the same for both an isolated p-type and n-type materials means that the absolute energy of an electron that is just outside the p type material is the same as the absolute ...
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How to get Miller indexes from a diffraction pattern?
Working with a single crystal, what is the first thing the diffractometer has access to? What is the output I see and what are the steps from this two levels of information?
If I'm correct, the output ...
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How can electrons hop large distances if they are connected to the atom which is stationary in an lattice?
How electrons in valency and flow as they are connected to the atom and the atom is stationary but the electron travels way more distance than the size of atom that causes conduction?
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Automated determination of invariant gauge group (IGG) of spin liquid mean field ansatz
In the Abrikosov fermion mean field theory of spin liquid, the spin-1/2 operator $\mathbf{S}_i$ on each site $i$ is expressed as
$$
\mathbf{S}_i = \frac{1}{2} \sum_{\alpha,\beta}
f^\dagger_{i\alpha} \...
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X-ray diffraction: coherence of the radiation source
In diffraction/interference processes I've always thought that coherence is an important condition for the source. If I well understand this is also why we choose punctiform sources of light which ...
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Resource recommendation for state of the art understanding of glass transition
Wikipedia identifies as an "Unsolved problem in physics" the question
What is the nature of the transition between a fluid or regular solid and a glassy phase?
citing a comment by Phil ...
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Is there an easier way to generate Brillouin zone $\mathbf{k}$-points of FCC lattice?
I am new to working with 3D lattices and am wondering if there are any well-developed methods for generating all $\mathbf{k}$-points inside the first Brillouin zone (BZ) of an FCC lattice.
I use the ...
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Is it possible to have a crystal structure where you are getting peaks of different intensities at different $2\theta$ values with same $hkl$ planes?
Is it possible to have a crystal structure. where you are getting peaks of different intensities at different 2thetha values with same h k l planes? What will you be calling that system to be a single ...
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The exact formula on relativistic electron degenerate pressure
I am studying white dwarf and I need relativistic electron degenerate pressure to calculate some physical problems like Chandrasekhar limit.
I only know that $p \approx n_e^{4/3}$ but the internet ...
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Near optimally doped superconductors' Ba isotope effect data precision
Is there any freely available transition temperature data for p-type cuprate superconductor samples around optimal oxygen content as a function of average barium isotope mass in a sample and oxygen ...
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Division by zero when evaluating the limit
Assume Bloch electrons, governed by the Schrodinger equation $H\psi_k=E_k \psi_k$, where $\psi_k$ is the Bloch function with eigen energies $E_{k}$ and band velocity $v_{k}=\partial_k E_{k}$ with $k$ ...
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Boundary conditions in quantum mechanics
I'm having some trouble understanding the role of boundary conditions in (non-relativistic) quantum mechanics.
EDIT:
The following text talks a bit about Bloch's theorem, but this was just supposed to ...
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Confusion between trigonal and hexagonal systems
I'm studying space groups.
It's quite clear (I think) why trigonal and hexagonal systems collapse in the same primitive Bravais lattice, while are different when we introduce non-primitive unit cells, ...
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Electrons in fractional quantum hall effect
Can we infer from plasma analogy in fractional quantum hall effect that the electrons fractional quantum hall state are all fractionalized? I have heard before the electrons in the state will be ...
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What is the cause of magnetization?
the relation between magnetic field strength and magnetic influx is: $H=B/\mu-M$.
M is called magnetization. In case of magnetic bar, it exists only inside the bar.
The relation is shown in this ...
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Excitation = Exciton?
I have a question regarding optical excitations: Do all optical excitations result in the formation of excitons? Specifically, I'm curious about the scenarios involving molecules with chromophores (...
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Cooper-Pairs: opposite $k$ but electrons moving in the same direction in real space? [duplicate]
I am learning about BCS theory and how Cooper pairs are formed. They have opposite $k$ and opposite spin. But what I do not understand is why Cooper pairs don't break up on their own. I have pictures ...
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Charge transfer broadening effect in solid state absorption spectra
What is the range of a broadening effect of a charge transfer absorption? Is it tenth's of eVs or different?
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Why the Moire Brillouin zone (BZ) of twist bilayer graphene is hexangular?
Usually, we have the definition of the basis vectors of Moire BZ, which is
\begin{align}
\boldsymbol{b}_1^m=\boldsymbol{b}_1-\boldsymbol{b}_1^\theta,\quad\boldsymbol{b}_2^m=\boldsymbol{b}_2-\...
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Jellium Hamiltonian in the thermodynamic limit
In Fundamentals of Many-body Physics by W. Nolting, 1e, the author arrives at the following formula for the electron-electron contribution to the Hamiltonian of Jellium:
$$
\hat{\mathcal{H}}_{ee}=\...
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Momentum space representaion of an electron-phonon coubling Hamiltonian
I am facing a problem transforming the following Hamiltonian into momentum space:
\begin{align}\hat{H} = -\gamma \sum_\alpha\sum_{i=1}^2 \hat{X}_{i,\alpha} \hat{c}_{i,\alpha}^+\hat{c}_{i,\alpha} +t\...
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The criterion about maximally localized Wannier function (WF)?
I heard that as the value of "num_iter(tag in wannier 90)" is higher, spread of Wannier function (=WF) is gradually lower in wannier 90.
If so, is this procedure that minimize the spread of ...
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Can field effect transistor s channel s varying depletion layers generate electric flux and control output current indirectly
Since magnetic field lines without need of contact attracts iron filing and drag them closer so that magnetic field line remain smallest.same analogy applied to field effect transistor ions in the ...
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Finding the classical antiferromagnetic ground state for the Kagomé lattice
I am attempting to do the following exercise in Altland and Simons Condensed Matter Field Theory:
"Show that the classical antiferromagnetic ground state of the Kagomé lattice – a periodic array ...
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$p+ip$ pairing in a spinless fermion system with attractive interaction
In this article (Section III.D), the following model of spinless fermions on the honeycomb lattice is considered:
$$
H = -t \sum_{\langle ij \rangle}
(c^\dagger_i c_j + h.c.)
- V \sum_{\langle ij \...
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Bloch oscillations and umklapp scattering induced by applied electric field
In Kittel's book chapter 8 there is a statement that says "The electron accelerates from
k = 0 toward the zone boundary; when it reaches k = pi/a it reappears (as by
an Umklapp process) at the ...
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Energy range when deriving heat capacity in Sommerfeld model
In my textbook, they assume a scenario in which the thermal energy of electrons is $k_BT << E_F$ , then only electrons which are near the Fermi level could be excited due to external thermal ...
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Other than approximating the total energy of the system, what other information does the Hartree-Fock method provide?
In the Hartree-Fock method, one computes the energy of an interacting quantum-many body system, described by $H$, via taking a non-interacting trial ground state, $|\psi_{\mathrm{HF}}\rangle$, and ...
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Can we tune chemical potential by electrostatic gating in solids?
I often hear that chemical potential in solids can be controlled by electrostatically gating the sample besides other methods such as chemically doping the sample. What are the limitations of ...
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Scattering into an edge state
In the optical context, a photon can excite an electron from the valence band to the conduction band if the photon energy is higher than the gap. I would like to know is it possible to photoexcite an ...
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What does a mechanical Josephson Effect look like?
This question is related to my research work in physics concerning the brittle-ductile-transition (BDT) in solid state mechanics, which ended quite some time ago and is summarized in my thesis from ...
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Using particle-hole symmetry of the Hubbard model to study the model at different densities
In Condensed Matter Field Theory by Altland and Simons, they state that the Hubbard Hamiltonian
$$
H = \sum_{\text{nearest neighbors } ij \text{ and spin } \sigma} a^\dagger_{i\sigma} a_{j\sigma} + U \...
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How do you see that the Wannier functions are localized on ion sites?
In Condensed Matter Field Theory by Altland and Simons, when discussing the tight-binding approximation for a lattice system with a periodic potential, they define the Wannier states as follows:
$$
|\...
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What is the criteria of forming a phonon polariton?
It is well know that, phonon polariton is a quasiparticle formed by the interaction between photons and optical phonons. But, does it mean that, any photons that are resonant with phonons can form ...
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Solid-on-solid models
I'm currently wondering about the so-called Chui-Weeks model 1 2, given by
$$ H = J \sum_i |h_i - h_{i+1}| + K\sum_i \delta_{0,h_i}, $$
which is a type of solid-on-solid (SOS) model used to describe ...
