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.

Filter by
Sorted by
Tagged with
1
vote
0answers
12 views

A quick and automated way to check if symmetry (point group) operations preserve a lattice

Suppose you look at the simple cubic lattice. There are symmetry operations which preserve the lattice symmetry such as translations and rotations around certain axes. There are also symmetry ...
0
votes
0answers
40 views

Crystal lattice Fourier coefficient

In solid state physics we have a periodic function over the lattice as $$f(\boldsymbol{r})=\sum_{\boldsymbol{G}}f_{\boldsymbol{G}}\mathrm{e}^{2\pi i\boldsymbol{G}\cdot\boldsymbol{r}}$$ where $$\...
1
vote
0answers
14 views

Solar cell: Surprising change in EL for varying PEDOT:PSS-thicknesses

I am currently working on improving a solar cell, which is partly transparent and therefore utilizes two transparent electrodes (TCO on top and PEDOT:PSS on the bottom). As PEDOT:PSS alone is not ...
0
votes
0answers
12 views

How to calculate optical conductivity from numerical eigenstates of tight-binding model?

Let's say we have a 1D spatially inhomogeneous tight-binding model that does not have momentum as a good quantum number. We can numerically diagonalize it to get the spectrum and eigenstates. But how ...
0
votes
1answer
29 views

Why do we have to introduce quasiparticles in the Fermi liquid theory

Why is it necessary in Fermi liquid theory to introduce quasiparticles? I understand the notion of system where someone can turn on the interactions slowly (i.e., adiabatically), but I do not ...
0
votes
0answers
40 views

Why is silicon absorbing visible light?

Here it is shown that silicon absorbs visible light: but the band gap energy for direct transitions is 3.6 eV which does not match to this absorption coefficient. Instead, the band gap energy for an ...
1
vote
0answers
8 views

What is the effects on the electrical conductivity of a crystal structure if the Fermi sphere fits inside the first Brillouin zone

My explanation: If the Fermi sphere fits inside the first Brillouin zone then there are empty states between the 1st and 2nd Brillouin zone which electron can be excited into. Hence, the crystal ...
2
votes
1answer
49 views

Is there a physical meaning of the Fermi liquid parameters

In Fermi liquid theory we define two parameters $F_l^s = VN(\epsilon_F)u_l^s$ and $F_l^a = VN(\epsilon_F)u_l^a$ where V is the fermi-volume, $N(\epsilon_F)$ the density of states at the Fermi energy ...
0
votes
0answers
20 views

Can we study the effects of Quantum reflection on heavy atoms?

From what I've looked at, it feels like QR has only been studied on light atoms like He, Ne, Na, H, etc. But can we study this effect on heavy atoms like Rb-87. If not, is it because of the ...
0
votes
0answers
17 views

Scotch tape and graphene not just from mechanical layer separation but also from triboelectric potentials and realignment of atoms?

I’m sure many here are aware of the way some smart guy showed that he could make graphene with scotch tape by peeling two pieces apart with graphite flakes sandwiched in between the tape pieces ...
0
votes
0answers
16 views

Plateaus in Quantum Hall effect

Why do the plateaus in the Quantum Hall Effect appear phenemenologically? Something to do with the 1D transport for the edge states?
0
votes
0answers
17 views

Eigenvalues of Bose-Hubbard model

I want to see eigenvalue spectrum of Bose-Hubbard Hamiltonian. Can anyone send me the algorithm to write Bose-Hubbard Hamiltonian.
1
vote
0answers
28 views

How does this quantity transform under time reversal and inversion operation respectively?

Suppose $\psi_{nk}=e^{ikr}u_{nk}$ is the Bloch function of a periodic Hamiltonian $H(r)=H(r+R)$, where $H(r)\psi_{nk}=\varepsilon_{nk}\psi_{nk}$ and $H(k)=e^{-ikr}H(r)e^{ikr}$. What would the ...
0
votes
0answers
24 views

How to know the symmetry (point group) of crystal field in a material?

As an example, Let's consider a material $Ba_{2}YMoO_{6}$,(ref:PRB 81,224409), the space group of this material is Fm3m, the crystal structure is shown below (https://journals.aps.org/prb/abstract/...
1
vote
0answers
32 views

Why are we even assuming $\alpha Gb^2$+$\alpha Gb^2$ on one case and again $\alpha G(2b)^2$ on the other case?

My point of interest is to know where the energy of two edge dislocation system comes from ($\alpha Gb^2$+$\alpha Gb^2$).It not really the formula that I am looking for but essentially why are we ...
0
votes
0answers
38 views

What magnetic interaction makes spin not conserved?

If $[S_i,H]\neq0$ or $[S^2,H]\neq0$, we might say spin is not a good quantum number in the system. But is there any more practical or detailed criterion? Or certain families of magnetic interaction ...
2
votes
0answers
59 views

Renormalization of chemical potential $\mu$

In the book "Bosonization of Interacting Fermions in Arbitrary Dimensions" the author writes: "By defining $\mu$ to be the chemical potential of the interacting many-body system, one implicitly adds ...
0
votes
1answer
51 views

BCS theory and Cooper pairs

I'm studying superconductivity and BCS theory. Looking at the BCS ground state construction, I see two things that seem conflicting Occupation of Cooper pairs in BCS ground state (look at the figure ...
0
votes
1answer
21 views

A question on the transition matrix. (algebraic derivation)

I am trying to follow the derivation of the following identity: $$[\epsilon -H_0+i\eta]^{-1}T = [\epsilon - H +i\eta]^{-1}U$$ where $T$ is the transition matrix and $U$ is the potential caused by ...
3
votes
0answers
34 views

Effectively Lorentz-invariant interacting Lagrangians in solid state?

Are there any known examples in solid state physics when an essentially non-relativistic system in certain regime may be described by a relativistically invariant Lagrangian with an interaction? ...
0
votes
3answers
62 views

States of matter [closed]

I am curious what are the physical factors in nature that some atoms exist as solids while others as liquid gases etc. Why some atoms and molecules have large interatomic distances and why some have ...
2
votes
1answer
38 views

Interpreting phonon dispersion relations

I have been working with phonon dispersion relations for a while now on the topic of metamaterials (phononic band gaps). However, I still do not feel that I have fully grasped how to interpret these ...
0
votes
0answers
10 views

How to include the possiblity of Umklapp Scattering into transport calculations

I'm trying to calculate transport properties of a certain model with a Hamiltonian that has electron-electron interactions. I know that, in order to use the Boltzmann equation \begin{equation} 0=\...
2
votes
1answer
45 views

Sonority of metals [closed]

Is there any reasonable atomic theory which can provide a rational reason for the existence of sonority in metals? Almost all the non-metals do not exhibit sonority. Can it be correlated to the ...
0
votes
0answers
38 views

Will a metastable solid convert to it's more stable form upon heating to the transition temperature of the more stable form?

Let's say a solid has a stable phase (A) that exists below some temperature, T, and A transitions to another stable phase B above that temperature. If you take a solid sample of B and rapidly quench ...
1
vote
0answers
21 views

Cooling just one mode?

In the context of Brillouin scattering and Stokes/anti-Stokes scattering in a silicon waveguide, a speaker mentioned optical cooling, but apparently only cooling a single "mode" was cooled. I had ...
1
vote
1answer
43 views

How can we see the microstructure of steel samples at room temperature?

When we intend to see the microstructure of a steel sample at a temperature say 950 $^\circ$C they say we quench it in order to freeze the microstructure. However, if we quench it are we not going to ...
0
votes
0answers
21 views

Galfenol and internal pressure

Galfenol is cool stuff. It’s iron doped with gallium. When under several gigapascals of force it is able to convert applied pressure to electricity at 70% efficiency when under magnetic field. My ...
0
votes
0answers
27 views

applied voltage on n-typed semiconductor changes its carrier lifetime

An apparatus was constructed in the lab to measure charge carrier lifetime. An LED illuminates an n-typed germanium semi-conductor with a square function with a constant frequency (the period of the ...
0
votes
0answers
11 views

How are the two Stacking Faults namely intrinsic(formed by vacancy agglomeration) and extrinsic(formed by interstitial agglomeration) different?

Stacking Faults and its association with partial dislocations seem to bother me day in and day out.With regard to this I do not understand how Partial dislocations lead to stacking faults and not the ...
0
votes
0answers
19 views

Certain doubts in Lomer Cottrell dislocation

With regard to this particular phenomenon that occurs there are a couple of things that need to be addressed.Firstly,Why do I have a region of stacking fault in that particular junction. I mean why is ...
4
votes
0answers
36 views

Difference between permittivities eps-opt and eps-inf?

Very often in materials physics we are interested in the relative permittivity at optical frequencies, which is usually denoted by $\varepsilon_\text{opt}$ or $\varepsilon_\infty$. But I'm confused ...
1
vote
0answers
21 views

For what choice of the basis atoms origin the Structure Factor is real?

I have a Cuprite Structure: Now, given that I described this structure as a Simple Cubic lattice with a 6 atoms basis, I have to choose the origin for these basis atoms such that the structure ...
1
vote
1answer
34 views

Density of levels in Fermi-Dirac statistics

We know that $$ u=\int_{-\infty}^{+\infty} D(\mathcal{E})\mathcal{E}f(\mathcal{E})d\mathcal{E} $$ where $D(\mathcal{E})$ is called density of levels per unit volume. My textbook (Kittel) says that: $...
0
votes
1answer
34 views

In the ground state properties of electron gas, is $V$ the volume of all the metal or the volume of a cell of the lattice?

In the ground state properties of electron gas (Sommerfeld theory), is $V$ the volume of all the metal or the volume of a cell of the lattice? I thought the latter because the Born—von Karman boundary ...
2
votes
0answers
62 views

Band Structure for free electrons

Consider a BCC lattice. How can I explicitly calculate the expression of the n$^{th}$-energy band $E_n(k)$ with $n=1,2,3,4$ for free electrons from $\Gamma$ to $N=\frac{2\pi}{a}(1/2, 1/2, 0)$ as a ...
1
vote
0answers
22 views

Density of states LL in graphene [closed]

I am using the Kernel Polynomial Method to determine the spectral density of a 2DEG system that has been sujected to a perpendicular magnetic field B. I wish to determine (a) What the amplitudes of ...
1
vote
0answers
40 views

Cutting silicon wafers using sound?

I've heard about using particle accelerators to shoot particles a specific distance into a wafer to split it and it got me thinking, can we do the same with sounds? Link to a page talking about the ...
5
votes
1answer
61 views

Why the randomness in glass/water/air does not destroy coherence of light over fairly macroscopic scales?

When light passes through glass/water/air, photons are absorbed and re-emitted by the chemical bonds, so that the speed of light in medium is reduced. However, in these media, it would appear that the ...
0
votes
0answers
13 views

Fano factor measurements

I am looking for information on the measurements of the Fano factor, in particular in germanium. Does anyone know accessible papers?
0
votes
1answer
32 views

Does an insulator always contain the Fermi surface in the 1st BZ

I'm looking for a clarification about the classification of metals and insulators; is it correct to state that if the Fermi surface is contained into the first BZ, then the material is an insulator, ...
1
vote
2answers
63 views

Thermodynamics: how does the deformation of partially elastic materials produce heat?

When a perfectly elastic material is deformed, the energy associated with the strain remains stored in the body as elastic potential energy, called strain energy. Upon the removal of the deforming ...
1
vote
1answer
17 views

Metal-Insulator from number of atoms in the basis

I have an issue understanding what A&M means while saying this in chapter 12: It is a reassuring exercise to go through the periodic table looking up the crystal structure of all insulating ...
2
votes
1answer
75 views

Is resistance determined by electron mobility?

How Is resistance determined by electron mobility for a given resistor or wire.
2
votes
0answers
28 views

How is quadratic form of miller index useful?

I have seen that we have used the $h^2+k^2+l^2$ value for finding whether the lattice is BCC,FCC or simple cubic.Where is this factor coming from?Why can I not use the structure factor theorem ...
1
vote
1answer
17 views

What is Saturation Magnetization? and how to calculate it for given values of magnetic moment, lattice constant and Temperature

What is Saturation Magnetization? and how to calculate it for given values of magnetic moment, lattice constant and Temperature. I know that saturation magnetization is the state reached when , ...
0
votes
1answer
27 views

What are precisley energy band extremes?

So I've got an energy band that goes like $$E(k)=E_0-t\cos(ak)$$ Now, I have to calculate the group velocity at the extrema of the band, but it's not clear to me what a band extreme is, and how to ...
2
votes
0answers
52 views

1D density of states help

I am given a 1D band whose energy is $$E(k)=E_0-t\cos(ak)$$ Then I have to compute the DOS relative to that band. Here is my calculation: $$g(E)=\dfrac{1}{L}\dfrac{dN}{dk}\dfrac{dk}{dE}$$ where $\...
0
votes
0answers
20 views

Is dipole approximation can be used to calculate the coupling in tight bonding model?

In the tight bonding model: $$ H=\sum_{i}\epsilon_{i} c^{\dagger}_{i}c_{i}+\sum_{i\neq j}J_{ij} c^{\dagger}_{i}c_{j} $$ Can dipole approximation be used to calculate the coupling between states i and ...
0
votes
0answers
23 views

What are the landau parameters for thin film and ceramic of Lead zirconate titanate PZT at any particular concentration?

I have got the values for some PZT ( 60/40, 70/30, 80/20, 90/10, 50/50 - ceramic) but have not got for any PZT thin film other than PZT52/48. the coefficients for thin film and ceramic of PZT at ...