# 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.

3,110 questions
Filter by
Sorted by
Tagged with
7 views

### Difficulty on getting vortex solutions from BdG Equation

I am working with BdG Equation in Tight Binding formalism, that is, full microscopic theory of superconductivity. In all references that I read they say that it is possible to generate the Abrikosov ...
20 views

### How do (LCD) drawing tablets work?

I recently bought a cheap drawing tablet and the box tells that it work via LCD. So I googled shortly and found this. I only want to confirm that this is correct. Means, are these tablet really ...
• 1,323
31 views

### Why is expectation value of velocity of Bloch state not zero?

In condensed matter theory a Bloch state $$\psi_{nk}(x)=u_{nk}(x)e^{ikx}$$ satisfying the eigenvalue equation $$\mathcal{H}\psi_{nk}(x)=E_{nk}\psi_{nk}$$ has the expectation value of velocity given by ...
• 244
256 views

### Low temperature behavior for ferromagnets: theoretical and experimental discrepancies

This is in reference to page 326, 327 of introduction to solid state physics, 8th edition by Charles Kittel The mean field theory does not give a good description of the variation of $M$ at low ...
• 851
1 vote
62 views

### Why hopping term and overlap intergral always real in tight-binding model?

I'm learning tight-binding model of polyacetylene (-CH- chain) and get confused by the off-diagonal matrix elements of Hamiltonian and overlap matrix. For example, in all materials I can find, they ...
1 vote
39 views

### Completeness in Bloch states

We know from the Bloch theorem that, in a periodic potential, the eigen wave functions are $\Phi_{kn}(r) = e^{ikr} u_{kn}(r)$ where n is the band index. So the solution can be expanded by them. ...
• 111
1 vote
25 views

### Doubts regarding Ohm's resistance from impurity scattering

It is told that electrons can scatter on impurities in crystals, which leads to resistance and Ohm's law. My problem is that even though the potential is not exactly periodic, the wave packet can move ...
• 51
1 vote
13 views

### How can I create 4 atoms basis graphene in Vesta? [closed]

How can I create 4 atoms basis graphene in Vesta? This is the Poscar file for two atoms basis graphene. As an example. Similar to these I got to make a 4 atoms basis graphene primitive cell. graphene ...
• 11
1 vote
89 views

### How are electrons filled inside the bands of a semiconductor?

Is it like this: where one energy value which is a single line in the band can be occupied by multiple electrons - and by one energy value I mean that the exact/precise energy of all the electrons in ...
15 views

### Position of hole in a semiconductor

If there is a vacancy in the valence band does it imply that the hole is in the conduction band? Since the definition of "hole" is -k, -E. This is the way I interpreted the definition so I ...
1 vote
29 views

### Confusion regarding density of states

Density of states with respect to energy is often defined as the number of states at a particular energy level. But I find this definition ambiguous. Because according to Pauli exclusion principle no ...
40 views

### What is Wannier state in solid-state physics? [closed]

I only retrieved information about the Wannier function, but I still don't know exactly what the Wannier state is. I would appreciate it if someone could explain it.
• 21
27 views

### Is the physics of semiconductors explained by nearly free electron model or is there a better model [duplicate]

I am learning (independently) about semiconductors and the physics behind their properties. Is the current 'accepted' theory for the physics of semiconductors (Electronic band structure) based on the ...
38 views

### Transformation matrix for plane directions using Miller indices

Since the change in vector orientations from conventional hexagonal unit cell to an orthorhombic cell of a HCP is not just a simple rotation about the origin, would the transformation matrix of the ...
100 views

### How does the highest energy electrons diffuse to the p-side from the CB of n-side shift the entire band structure of n-side down

When an n-type material comes in contact with a p-type material to form pn-junction, electrons with the highest energy in the conduction band will diffuse to the p-side to reach equilibrium so the ...
• 15
33 views

### Fermi energy is the average energy possessed by electrons participating in conduction in metals at T>0K?

I don't understand why on pg 963 of the following book stating that Fermi energy is the average energy possessed by electrons participating in conduction in metals at T>0K. Should Fermi energy be ...
• 15
1 vote
23 views

### Why can't single particle states be taken up by more than one particle in the Fermi Dirac Distribution?

In Ashcroft, a single particle state is specified by k which is the wave vector of a single electron's wave function (without considering spin). Pauli Exclusion Principle says that a single electron ...
21 views

### What are the effects of Bravais lattices classification differences in 2D space on the physical properties of the crystals?

There are five possible distinct Bravais lattices in two-dimensional space. For example, if crystal A is Monoclinic (M) and crystal B is Hexagonal (H), how will the difference in their 2D Bravais ...
• 109
1 vote
42 views

### Regarding the Maxwell Boltzmann statistics

Maxwell boltzmann distribution is applicable when any number of particles can occupy a single-particle state. But I am confused about what exactly a "state" here refers to. When you think ...
1 vote
11 views

### Relation betwwen the expectation value of the position operator in Bloch state with unitary position operator

Recently, I want to get some knowledge about topological insulators, so I read the A short course on topological insulators. In the chapter 3, the author try to explain why polarization connects with ...
• 11
30 views

### Why do some minerals prefer diamond structures while others prefer wurtzite structures?

Carbon can exist as both diamond and wurtzite structures (lonsdaleite), but diamonds are much more common than lonsdaleites in nature. Some materials like GaN preferentially form wurtzite structures. ...
• 461
1 vote
76 views

### PN junction - Voltage difference in neutral regions

At the very moment when a p material and a n material are put together, the conduction band and valence band of both materials are at approximately the same level. The n side and p side are both ...
• 15
1 vote
36 views

### Property of reciprocal lattice

I came across the following property of the reciprocal lattices. Let be $\Lambda$ a Bravais lattice and $\Lambda^*$ its reciprocal lattice; let be $\vec{G} \in \Lambda^*$ and $\vec{G}_0$ the shortest ...
29 views

### Width of the Plateauxs in the IQHE

As the title said, Im studying the IQHE and I would like to know if there is some theory or idea to understand the widths of the Plateauxs that can be seen experimentally. As you can see in this ...
1 vote
27 views

### Introduce a model with logarithmic dispersion relation

Having a model Hamiltonian on a lattice, one can compute the band structure of a system by employing the Bloch theorem. Here for simplicity, let's focus on noninteracting models. This procedure for a ...
• 374
32 views

### Time evolution of operators in linear response theory (Kubo formula)

I am reading the following book Many-body quantum theory in condensed matter physics book by Henrik Bruus and Karsten Flensberg This book mainly focuses on time-independent Hamiltonians only. When ...
• 535
1 vote
77 views

### Is it correct to describe the valence electrons in an insulator as being bound to specific atoms?

For some quick background, I work as a high voltage electrician at a major metropolitan utility. In training apprentices, we use books that are often very poor in explaining fundamental electrical ...
• 31
26 views

### Calculating degeneracy in Landau Gauge with fixed boundary conditions

In another question I asked the differences between aplying periodic boundary conditions and fixed boundary conditions. The answer is that both of them for large enough samples present the same amount ...
148 views

### Landau Levels degeneracy in a finite sample

According to different sources: Tong lectures on IQHE (Tong), MIT Open courses (MIT) etc, when calculating the number of states in each Landau Level all of them impose (in the Landau gauge) periodic ...
1 vote
31 views

### Interaction Term in Tomonaga-Luttinger Model

I am studying Tomonaga-Luttinger Model from Altland and Simon's textbook called Condensed Matter Field Theory. From the derivation, I am stuck with showing that the contribution to the interaction ...
• 321
1 vote
18 views

### Polarization of conduction and valence bands

As title, this is something that I read in the paper "Quantitative relationship between polarization differences and the zone averaged shift photocurrent" (PRB 96, 075421 (2017)). This paper ...
• 11
24 views

### How do we measure the crystal momenta and the corresponding energies?

Determination of crystal momentum and the corresponding energy seems to be essential for drawing the band structure. What is the principle that is used to measure the crystal momentum and the ...
• 9,685
62 views

• 27
484 views

### How to understand electron drift velocity?

I know that electron drift velocity can be defined as $I$ = $nAve$, where $I$ is the electric current, $A$ is the cross-sectional area of a conductor, $v$ is the electron drift velocity in question, ...
• 308
1 vote
43 views

### Understanding the bandgap in $E-k$ diagram in the nearly free electron model

The nearly free electron model, solved using perturbation theory, reveals that a band gap opens up at each Brillouin zone boundary. Why is a point just below $k=\pi/a$ lowered in energy and a point ...
• 9,685
33 views

### Effective mass tensor calculation by fitting band structure along 3 perpendicular direction, correct or not?

The effective mass of charge carriers is defined as $$\left(\frac{1}{m}\right)_{ij} = \frac{1}{\hbar^2}\frac{\partial^2E }{\partial k_i \partial k_j}$$ Considering that at the CBM we have a parabola....
• 43
37 views

### Confusion regarding calculation of effective mass tensor

I want to calculate the effective mass tensor as has been done in this paper. The authors go about calculating the effective mass in , and  for a few different compounds, by curve ...
• 43
5 views

### Change in electronic dispersion in presence of magnetic moments

What happens to the energy dispersion of electrons in a 1D lattice in presence of localized magnetic moments on the lattice sites? Let's take both of ferromagnetic and antiferromagnetic configurations ...
• 161
66 views

• 51
17 views

### Is it possible that a phonon having the same momentum $q$ after an scattering event?

We went through different phonon scattering events in my lecture. We looked at: Surface, surface roughness, impurity and "Umklappen" scattering. All those events changed the wavevector q of ...
• 31
1 vote
51 views

### How to calculate the energy of a spring-mass system considering harmonic oscillation of the normal mode? [closed]

For a spring-mass system, we know that the potential and kinetic energy are $$E_p = \frac{1}{2}ku^2 \text{ and } E_k = \frac{1}{2}m\dot{u}^2.$$ where $k$, $m$ and $u$ are the spring constant, mass and ...
1 vote
51 views

### Square lattice in the magnetic field; can someone please explain hopping factor Hofstadter uses?

If we have a square lattice in a homogenous magnetic field $\vec{B}=(0,0,B)$ and we use the Landau gauge for the magnetic potential $\vec{A}=(0,Bx,0)$; then, I have two questions: QUESTION $1$. Is the ...
• 27