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.

learn more… | top users | synonyms

1
vote
1answer
36 views

How does the surface of a material always break inversion symmetry?

I am trying to visualize this for an HCP structure. Take the profile view as such: just working in 2d. So my understanding is if we can take a point (x,y) -> (-x,-y) and get the same crystal than ...
3
votes
1answer
53 views

Free electron Gas shortcomings

I am studying surface states and the Rashba effect. A common model I keep coming across is to implement the free electron model. In this model we get the spin orbit interaction Hamiltonian by ...
5
votes
1answer
77 views

Why are periodic boundary conditions used for the derivation of phonons? [duplicate]

I am currently reading "Quantum Field Theory for the Gifted Amateur". In chapter 2 Phonons are introduced as solutions (in k-space) of a coupled harmonic oscillator. In real space the oscillator is ...
1
vote
0answers
9 views

Surface potential and symmetry breaking

I am studying surface states currently and am a little confused about something. If I consider p-orbits on a surface state that is the top layer of an HCP structure -- I understand the hopping terms ...
3
votes
0answers
41 views

Linear Response And path integral

I'm following Wen's book on Quantum field theory, and I'm struggling with section 2.2.1 on linear response and response functions. Specifically I'm unable to reproduce equation 2.2.7 in which the ...
0
votes
1answer
32 views

When a liquid solidifies why does internal energy fall? [closed]

Is it because the potential energy falls or is it because the kinetic energy falls .
0
votes
1answer
28 views

What is difference among the consepts: bulk free energy, cohesive energy, Gibbs free energy, binding energy?

I am working on size dependent surface energy of metals. I need to know the different energies between the atoms. Different papers use different energies but their meanings seem alike, therefore they ...
1
vote
1answer
95 views

Energies in Band Alignments

There is something that I would like to confirm regarding the energy when aligning the bands of heterostructures. There seems to be a general consensus that there is no simple rule to align two ...
0
votes
0answers
14 views

Derive Fermion Particle Density Operator in q-space

I am reading Bernevig's Topological Insulators and Topological Superconductors. In section 3.1.1, it gives an expression for the Fourier transformation of electron density operator, which I cannot ...
0
votes
0answers
14 views

Creation operators that differ by a reciprocal lattice vector

In very general terms, if you have an infinite lattice of atoms you can describe the physics in terms of creation (and annihilation) operators $\hat{a}_{\mathbf{R}}$, that create (and annihilate) an ...
0
votes
0answers
24 views

What's the difference between an exciton and a geminate pair?

In the context of organic solar cells, electron-hole dissociation is sometimes mentioned with regard to excitons (refs 1, 2) and sometime with regard to geminate pairs (refs 3, 4). Also, exciton ...
1
vote
0answers
10 views

Why singlet and triplet states are not mentioned when dealing with inorganic semiconductors or other heavy materials?

Singlet and triplet states get attention in organic materials (fluorescence, phosphorescence, upconversion). Why singlet/triplet states are never mentioned in the context of inorganic semiconductors, ...
0
votes
0answers
18 views

What is a surface dipole? What is an interface dipole?

I often see the these two terms in solid state physics. However, I couldn't find any explicit definition for them. Are they simply dipoles that happen at a surface or at an interface or is there more ...
0
votes
0answers
7 views

Degree of inhomogenous broadening for NV ensembles

what is the inhomogenous broadening in a NV ensemble? this means what is the spread in the energies of different NV centers in an ensemble?
1
vote
1answer
42 views

Hartree-Fock orbitals of a periodic crystal -> Bloch waves?

I am wondering how I can see that the Hartree-Fock orbitals of a periodic crystal obey the Bloch theorem? My problem is that the Hartree-Fock Hamiltonian does not have the form $-\frac 1 2 ...
1
vote
0answers
21 views

Why isn't every magnetic neutron scattering peak a nuclear scattering peak as well?

Neutron diffraction is a well-established technique for determining the magnetic unit cell of magnetic materials. The idea is that nuclear scattering gives you peaks that correspond to the crystal ...
0
votes
3answers
53 views

Pressure or confusion

We all know that pressure is force per unit area. for example we have a pressure of $5N/m^2$, so is the load of $5 N$ acts on the entire area or it acts just at a point i.e. is the load a point load ...
0
votes
0answers
17 views

Commutation of photonic crystal master equations

In studies of photonic crystal's, there are two "master equations" for the electric and magnetic fields: ...
0
votes
0answers
8 views

Electronic Transport not covered by Bandstructure in Solid State Physics

From what I have read, most of the electronic transport phenomena in solids state physics seems to able to be determined with the bandstructure. Schottky Barriers, bandgaps, band discontinuities can ...
1
vote
1answer
39 views

Difference Between Ruderman-Kittel-Kasuya-Yosida (RKKY) Interaction and Kondo Effect

The question is in the title. I don't understand the difference between these two effects. Based on my understanding, the Kondo Effect is where the conduction electrons effectively screen a local ...
1
vote
0answers
6 views

Hopping integral for Hydrogen chain

When calculating a hydrogen chain in the tight binding approx., one comes across the hopping integral: $<m+1|V_{m+1}|m>$ Where $|m>$ is the 1s-Wavefunction at position m and $V_m$ is the ...
2
votes
0answers
24 views

Are Dirac points the norm for 2D band structure?

I've been doing simulations of band structure for 2D optical lattices, and something I've noticed is that, for sufficiently shallow lattices, there are typically points on the edge of the first ...
2
votes
0answers
46 views

Non-physical representations of double group

In group theory, to account for electron spin, double group is introduced. The key difference between an ordinary point group and a double group is an extra element $\bar{E}$ with the meaning of a ...
2
votes
1answer
49 views

Localized Phonon Vibrational Modes and Thermal Conductivity

I chanced upon this 1D chain Mass Impurity model: At the end of all the derivations, it concludes that Case 1: $ 0 < M_0 < M$ The impurity is lighter than the host atoms. The frequencies ...
1
vote
0answers
38 views

How to write Fractional Quantum Hall States with Symmetric Polynomials?

Is there a link between Fractional Quantum Hall States and Symmetric Polynomials. In papers of Xiao Gang Wen [1], [2] work out a few examples: $ \Phi_{1/2} = \prod_{i < j} (z_i - z_j)^2$ is the ...
0
votes
1answer
14 views

Does the Schottky Barrier only happen at Metal Semiconductor Interfaces?

Most references that I have come across refer to the Schottky Barrier in the setting of Metal and Semiconductor Interface. Would it be correct to use the term Schottky Barrier to refer to the mismatch ...
5
votes
2answers
404 views

How does an electron move through a metal or a semiconductor

I understand that atoms in a metal or semiconductor are bonded and that they will have several eigenstates where electrons can reside. When a voltage is applied electrons in eigenstates will move to ...
3
votes
0answers
30 views

How to determine the direction of the wave with the wave vector at Gamma point in the Brillouin zone center?

In the Brillouin zone, such as M point in the Brillouin zone of hexagon lattice, we can determine the direction of this wave vector in the real space; however, for Gamma point,I can't determine the ...
0
votes
0answers
15 views

Are the dative bond electrons less localized than other covalent bond electrons?

Are the dative bond electrons less localized than other covalent bond electrons, since the dative bond electrons come from same atom and the other atom handles extra electron.?
1
vote
1answer
34 views

Nonzero stress on crystal at equilibrium volume?

Using a first principles computational method such as DFT, you can calculate the energy of a unit cell at different volumes to obtain a parabolic energy vs. volume curve. The minimum of this curve ...
0
votes
0answers
25 views

Maximum Phonon Frequency

If I am given the maximum Phonon energy in a monotonic lattice, how would i go about finding the max frequency ? Would this be taking the max energy and dividing by h-bar to give the max frequency ? ...
1
vote
1answer
52 views

When you push a stick will the end of it respond later than the beginning? Is so what is the fastest material and what forces are involved?

Normally when two people hold a long stick the receiving person would feel at the same time the stick moving when the first person gives the stick a push. But is that in reality exactly the case? ...
0
votes
0answers
19 views

Analytical derivation of photonic bandstructure in photonic crystal

It seems the usual way to find the photonic bands of a photonic crystal is to setup the "master equation" $$\nabla\times\left(\frac{1}{\epsilon(\mathbf{r})}\nabla\times\mathbf{H}(\mathbf{r}) ...
15
votes
2answers
447 views

What is “Dynamical phase transition”?

What is "Dynamical phase transition"? It is a fancy notion now. But what exactly does it mean? What is the difference between it and the conventional phase transition?
0
votes
0answers
23 views

Polarization current introduced by induced charge?

Should we count the current density that introduced by the movement of induced charge as free current or magnetized current or neither? And why?
0
votes
0answers
14 views

Temperature dependence on conductivity of a metal in terms of band gap, conduction band, valence band,

I am trying to find an answer to the following question: Why did the conductivity of one of the metals decrease with increasing temperature? Explain in terms of ...
1
vote
2answers
94 views

Physical meaning of crystal momentum

I am familiar with some of the definitions of crystal momentum and I am familiar with how it is related to Bloch's theorem. I also am familiar that crystal momentum is not the momentum of each ...
0
votes
0answers
37 views

Construction of Wannier function for optical lattice potential

Parameters of the Bose-Hubbard model require the knowledge of the Wannier functions from the lowets band of the optical lattice potential $V(x) = V_{0}\sin^{2}(kx)$ according to equations: $$J = \int ...
2
votes
1answer
62 views

What does the solid phase in a two-dimensional system with Lennard-Jones potential look like?

Consider a system of two dimensional particles interacting via Lennard-Jones pair potential: $$u(r) = 4[(\frac{1}{r^{12}})-(\frac{1}{r^{6}})]$$ where r is the distance between two particles. What does ...
0
votes
0answers
26 views

How can a metal and an insulator have high dielectrics yet one is conducting and one is insulating?

I don't get it: insulators are referred to as dielectrics. The higher the dielectric the higher the insulation(?). But the dielectric constant of metals is considered infinite. Aren't they supposed to ...
1
vote
1answer
32 views

What does it mean lattice softening and stiffening?

Which kind of proceedings does it pretend? And why it is applied to examine high temperature superconductivity?
1
vote
0answers
13 views

How Cooper pairs conduct curent [duplicate]

we know that electrons in superconductor are coupled somehow (How does Cooper pairing work?) creating quasi-particles called cooper pairs which are Bosons and going to ground state ( do not obey ...
0
votes
0answers
11 views

conduction mechanism

How can someone distinguish between hopping and thermal activation conductivity respectevely, if in a Arrhenius plot (Log[σ] to 1000/T) the activation energy is constant and independent of DC electric ...
2
votes
1answer
50 views

Why do we use the anticommutation relation for particle-hole and chiral symmetries?

In physics we say that a quantity is conserved if its operator commutes with Hamiltonian. For example, in condensed matter systems, when the momentum $k$ commutes with the Hamiltonian $H$ as ...
1
vote
0answers
11 views

In non-metallic solids w/ just atoms or ions (no molecules), are bonds (vibrations) and electronic transitions the sole cause of blackbody radiation?

Since there wouldn't be a conduction band filled with any electrons in a non-metallic solid made of just atoms or ions (no molecules), it's hard to imagine any other type of movement and dipole moment ...
0
votes
0answers
20 views

Are k-points in the reciprocal lattice, points where constructive interference is the strongest?

I saw a video on youtube that seemed to imply that k-points are the positions where constructive interference is strongest. The link is https://www.youtube.com/watch?v=DFFU39A3fPY Is this true? I ...
0
votes
0answers
100 views

Derivation of the Brillouin function

In a Solid State Physics problem, I am asked to demonstrate that the magnetization of a set of atoms or ions with identical angular momentum $J$ is proportional to the Brillouin function, defined as ...
1
vote
0answers
19 views

The probability of photoluminescence

Was reading about premeditated doping in semiconductors and the effect it imposes on the emission spectrum, doping as I read introduces defect states which are close to either the valence band edge or ...
0
votes
3answers
45 views

Number of atoms in HCP unit cell

Whenever the atomic packing factor for the hexagonal close-packed (HCP) crystal structure is discussed, such as in this wikipedia article, it is stated that the (effective) number $N$ of atoms in a ...
0
votes
1answer
26 views

How is Q-carbon made?

How is Q- carbon made ? https://en.wikipedia.org/wiki/Q-carbon Why a nanosecond laser is needed? How is it cooled ?