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
votes
0answers
39 views

Books about temperature dependence of resistivity

Can someone suggest me books about the relation between temperature and resistivity. I need books that go deep into that.
2
votes
1answer
37 views

The 1-dimensional Kronig-Penney Model: Trying to understand the relation between hopping energy and effective mass

The 1-dimensional Kronig-Penney Model predicts a relationship between energy, $E$ and wavenumber, $k$ of the form: $$\cos(ka)=\cos(qa) - \frac{m_e\,A\,t_0\,\sin(qa)}{\hbar^2\,qa}$$ where $$q=\sqrt{\...
0
votes
0answers
15 views

Quotient of Radii for Sodium Chloride

In a lecture of Solid-State Physics, we covered the following slide: $\alpha$ is the Madelung-constant, but I would like to understand why (i) $$\frac{r_{-}}{r_{+}} < \frac{1}{\sqrt{2}-1}$$ and (...
1
vote
1answer
30 views

Why are x-rays not produced using solid-state devices?

Recently, I noticed that most devices that produce X-rays are somewhat 'crude'. It is usual for these devices to either heat something up to the point where the bremsstrahlung is in the X-ray region - ...
1
vote
0answers
24 views

How to prove $E_{k+G}=E_{k}$ in solid state physics when T is degenerated using Bloch theorem?

In several textbooks I read about solid state physics, the way to introduce the first Brillouin zone and the energy band structure is like the this: Step 1: The Hamiltonian could be diagonalized by a ...
1
vote
0answers
17 views

Hall coefficient for metals negative

I am wondering why the Hall coefficient for Al is negative, I am thinking about holes (I understand how holes word in semiconductors, but I can not use that because metals have no bandgap...), but I ...
0
votes
0answers
22 views

As the temperature increases,the resistivity of conductor also increases why? [duplicate]

As the temperature increases, the resistivity of conductor also increases why?
2
votes
2answers
48 views

Effect of the number of atoms in the basis to the heat capacity (component of the phonons)

I am wondering what's the effect of the number of atoms in the basis onto the heat capacity (phonon part). I've found this post: How the number of atoms in the basis affects the density of states? ...
2
votes
2answers
66 views

Generalisation of the density states of phonons

Is it possible to generalize de density of states for phonons $\left( \left(\frac{L}{2\pi} \right )^3 \int \frac{dS_\omega}{v_g}\right)$ to a density of states which is also applicable to Bloch ...
1
vote
0answers
26 views

How to calculate spin correlation function via spin coherent state?

I am following the Section 8.3.1 of Auerbach. I want to calculate spin correlation function via spin coherent state, i.e. the equation (8.28): $$\begin{aligned}\left\langle\mathbf{S}_{m} \cdot \mathbf{...
2
votes
1answer
41 views

Density of states: Debye phonons vs free electons

In the Debeye approximation the density of states goes with phonon-energy^2, while the density of states for free electrons goes with sqrt(energy of the electrons), why is that? (I use Introduction ...
1
vote
1answer
31 views

Why does adding a photon to the crystal of a semiconductor, gives a vertical transition in the reduced zone scheme?

Why does adding a photon to the system, gives a vertical transition in the reduced zone scheme? Considering me, it's due to the fact that a photon does not change de $k$-vector, is that correct? And ...
0
votes
0answers
18 views

How to find the density of states from the dispersion relation numerically [closed]

I have a dispersion relationship as follows, (it is two-dimensional) $\omega=\sqrt{2 \frac{f}{m}\left[3-\cos k_{x} a-2 \cos \left(\frac{k_{x} a}{2}\right) \cdot \cos \left(\frac{\sqrt{3}}{2} k_{y} ...
0
votes
0answers
10 views

Thickness-dependence of diffraction intensity in single-scattering regime?

Is the thickness of a sample related to the intensity of x-ray diffraction? seems to ask about the thickness-scaling of diffraction intensity in crystallography, but in the body it refers only to ...
0
votes
1answer
45 views

Hamiltonian in real and reciprocal space

I found that sometimes people mentioned that Hamiltonian in real space or Hamiltonian in reciprocal/$k$-space. I wonder what difference of Hamiltonian in real and reciprocal spaces are? For example, ...
1
vote
1answer
29 views

Temperature dependency of electron density in metals

I wanted to know how the electron density in metals behaves with temperature. I couldn't really find an answer online so I searched through my x-years old scripts and, surprisingly, I found a sentence ...
0
votes
0answers
16 views

The dispersion relationship and density of state of the 2D simple triangular lattice

Calculate the dispersion relationship and density of state of the 2D simple triangular lattice. Suppose the atomic mass is m, the distance between adjacent lattice points is a, and the atoms of ...
0
votes
1answer
25 views

What does it mean to say that the Fermi energy is equal to the hopping energy?

I have a conceptual question regarding the relation between hopping energy and Fermi Energy. In order for my question to make sense contextual background is needed: So the hopping integral or ...
0
votes
2answers
37 views

Why doesn't the depletion region completely vanishes in a p-n junction in forward biased condition?

Can anyone explain why does the depletion region not vanish completely, but only shrinks, on forward bias?
1
vote
0answers
23 views

Does the Mott metal-insulator transition occur with increasing or decreasing density of valence electrons?

When reading about the Mott metal-insulator transition, it has not become clear to me if the transition from a metal to an insulator occurs with increasing or decreasing density of valence electrons. ...
1
vote
0answers
22 views

Physical Intuition of Inelastic Mean Free Path

The inelastic mean free path (IMFP) is a quasi-universal curve which describes how far a beam of electrons will travel through a material before scattering inelastically. I have been searching for ...
0
votes
1answer
30 views

Amount of free electrons in a metal

How can I calculate the amount of free electrons in a metal? I search the forum but found nothing What I want to know is how many electrons can I remove from a metal using photoelectric effect (...
0
votes
0answers
17 views

Do conductors have temperature coefficient of resistance of order $0.1$ [1/K] at $40 - 160$ Kelvin?

Typical metals have temperature coefficient of resistance with order of magnitude $\sim 0.001$, at $20$ degrees Celsius. What kind of materials have TCR of order of magnitude $0.1$ at $40 - 160$ ...
0
votes
0answers
18 views

Limit evaluation on Kronig Penney Model

I am a beginner to QM and was studying about the Kronig Penney model and understood the derivation of the following equation, $$ \cos(ka) = \frac{P}{\lambda a} \sin(\lambda a) + \cos(\lambda a)$$ ...
1
vote
0answers
16 views

Can someone explain why electrons of n type(conduction band,higher energy),fall into holes in p type(valence band,lower energy) during forward bias?

As I was learning semiconductor physics I learned that holes are deficiency of electrons.I also learned that the electrons from the n type material combine with the holes in p type and the electrons ...
0
votes
0answers
12 views

Can you apply horizontal shift to obtain the absorption spectra for III-V ternary and quaternary compounds

For a multi-junction (MJ) solar cell application, can you apply a horizontal shift to obtain the absorption spectra when you don't have the available data? For example, if you know the absorption ...
0
votes
0answers
26 views

“Lorentz transformation” for general dislocation

Let's fix a coordinates system $(x,y,z)$ with origin $O$. Considering a (screw or edge) dislocation and let the coordinate system $(x',y',z')$ with origin $O'$ move with the dislocation, and impose ...
1
vote
1answer
27 views

Calculation of effective mass from bandstructure

The effective mass is defined as $$ \frac{1}{m_{ij}^*} = \frac{1}{\hbar^2} \frac{\partial^2\epsilon}{\partial k_i \partial k_j} $$ where, $m_{ij}^*$ is the effective mass, $\hbar$ is the Planck's ...
0
votes
1answer
27 views

X ray diffraction and the band theory

I was look around stack exchange and couldn't find a good answer to this: What is the relation of the band theory of solids and the X-ray diffraction? We know that it EM wave is scattered (the process ...
0
votes
2answers
39 views

Dispersion relation near Brillouin zones - Periodic potentials

I am trying to wrap my head around periodic potentials and weak periodic potentials from the reduced zone schemes. From the definition of $\psi_k$: $$ \psi_k(x)=\sum_G C_{k-G}e^{i(k-G)x} $$ I ...
0
votes
0answers
22 views

Nearly-free-electron model in 2D

I'm trying to compute the first five energy gaps at the point (1,0) for nearly free electron in 2D lattice. Where the potential is describe by V(r) = e$^{\frac{-\mid r \mid}{b}}$ (A, b constants and r ...
1
vote
1answer
39 views

Intrinsic carrier concentration and bandgap

My understanding is that the intrinsic carrier concentration of a wide bandgap material tends to be lower than that of a narrow bandgap material. $$ n_i = \left(N_cN_v\right)^{1/2}e^{\left(\frac{-E_g}...
0
votes
0answers
25 views

Fermi Energy in Anisotropic Crystal

Suppose I have an anisotropic cristal, so it has, say, energy $$E=a(k_x)^2+b(k_y)^2$$ How would I calculate its Fermi energy? It doesn't depend only on the length of the vector $k$, so most of the ...
0
votes
0answers
18 views

2 different density of states for Graphene and Bismuth Selenide

I will solve the problem below by $1)$ working in reciprocal (wavenumber space) and in $2)$ energy space ($\epsilon$). But first some contextual background: Graphene is a single sheet of carbon ...
0
votes
1answer
21 views

How to know a semiconductor is p type or n type from hall effect calculations? [closed]

Using the hall effect calculations how can we determine a semiconductor is p type or n type
0
votes
1answer
55 views

The most general $SU(2)$ invariant spin $\frac{1}{2}$ hamiltonian on 5 sites

I have periodic chain of spins $s=\frac{1}{2}$. I want to know what is the most general $SU(2)$ invariant and translation invariant hamiltonian. My guess is: $$\sum_i (j_1 S_i \cdot S_{i+1}+j_2 S_i \...
4
votes
2answers
79 views

Why are electrons in solids always considered to be in energy eigenstates?

When studying the properties of solids we always say that electrons are in (stationary) energy eigenstates. The theory of conduction for example (with conduction bands and stuff) follows from the ...
0
votes
1answer
22 views

Why only the electrons around the Fermi energy gain energy when a material is heated?

I am reading Introduction to Solid State Physics (by Kittel). When studying the heat capacity of a metal, conformed by $N$ atoms (each providing one valence electron, which is mobile and capable of ...
3
votes
0answers
75 views

Calculating the inelastic quasiparticle lifetime of a screened quantum fluid

I've been studying "Lifetime of a quasiparticle in an electron liquid", by Qian and Vignale. Much of it makes sense, but there is a detail in the calculation of the exchange term that doesn't make ...
0
votes
1answer
22 views

Does band structure diagram tell anything about position of the particle?

What is the physical interpretation of the electronic band structure diagram and wave vector $k$ in solid-state physics? Does $k$ tell something about the direction of moving electron/particle? The ...
2
votes
1answer
46 views

Does the shifting of the Fermi energy level of an intrinsic semiconductor mean that $n \neq p$?

It has been stressed out in the books that I've consulted that, for an intrinsic semiconductor, $n=p$. However, with this in mind, they also derivate the following equation: $$E_{F_i}=\frac{E_c+E_v}{...
0
votes
1answer
23 views

Question on semiconductors and band gap at absolute zero

I was reading a book on Solid State Physics which stated that insulators have a band gap larger than 3eV, insulators <3eV and metals have no gap. It also states that semiconductors become ...
0
votes
1answer
18 views

Sound wave direction of polarization in liquid and solid

In Statistical Physics, part 2 by Landau and Lifschitz, second 22, it's written that the sound wave only has longitudinal direction of polarization in liquid while both longitudinal and tranverse in ...
0
votes
1answer
45 views

Metal-insulator transition (material properties)

When studying about metal-insulator transitions, I was wondering which material properties can give direct information about this phenomena. Also, what information can be derived from these properties....
0
votes
1answer
18 views

Trying to understand crystal structures within a solid

I am trying to get a firm understanding of crystal structures in solid state physics but having some issues with the terminology. If I understand correctly, the lattice are points in a 3-D space so ...
2
votes
2answers
20 views

Does solar cells absorb sub-bandgap photons?

My understanding is that although we are taught that solar cells only absorb photons of energy higher than the bandgap of the material, some of the sub-bandgap photons still gets absorbed, which is ...
0
votes
0answers
11 views

Solid state physics - Why do the valence electrons of 2 diff atoms tend to occupy the same energy level? (Eventually leading to splitting)

So, I was watching this lecture on the band formation in solid crystals. There was this part where they lecturer was talking about bringing 2 atoms A and B close to each other from infinity. When ...
1
vote
0answers
24 views

Berry curvature for spin in a magnetic field

Does anybody know how to compute the Berry curvature for a spin with angular momentum $s$ (so it's not the usual derivation you find for spin-$\frac{1}{2}$ particles in most textbooks) in a magnetic ...
1
vote
0answers
22 views

Taylor Expansion of Molar Heat Capacity

in a lecture, we obtained the following expressing for the molar heat capacity according to the Einstein-modell: $$C_{\text{V, mol}} = 3R\left( \frac{T_E}{T} \right)^2 \frac{\exp\left( \frac{T_E}{T} ...
6
votes
0answers
195 views

Magic angle graphene

In this article here, it is claimed that the following model for bilayer graphene $$\mathcal H= \begin{pmatrix} 0 & \mathcal D^*(-r) \\ \mathcal D(r) & 0 \end{pmatrix}, \mathcal D(r)=\begin{...

1
2 3 4 5
46