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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Difference between steady state and equilibrium?

In semiconductor physics, what is the difference between steady state and equilibrium. How analysis of devices varies in these processes?
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Fermi level alignment and electrochemical potential between two metals

I'm trying to get a more intuitive/physical grasp of the Fermi level, like I have of electric potential. I know that, for just a single piece of metal in equilibrium, you have to have the electric ...
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143 views

Liquid benzene magnetic susceptibility

In a solid state physics problem, I'm asked to make a rough estimate of the contribution to the diamagnetic susceptibility of the outer electron of each carbon atom. The wavefunction of these ...
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How can crystal structures be determined using X-ray diffraction?

You have the intensity peaks and the diffraction angles. Let's say you suspect the material is cubic, how do I find if it's simple cubic or BCC or FCC? I've googled and all my textbooks just state ...
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453 views

What is different between resolvent and green function

I bumped into a book, where Resolvent $R^{\pm}(E)$ is defined as $e^{\mp iHt/\hbar}=\pm\frac{i}{2\pi}\int_{-\infty}^{\infty}dER^{\pm}(E)e^{\mp iEt/\hbar}$ and $R^{\pm}(E)=\frac{1}{\pm ...
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What is the difference between contact-limited and space-charge-limited charge transport?

I am reading a paper ("Tunable Electrical Conductivity of Individual Graphene Oxide Sheets Reduced at 'Low' Temperatures," Jung, et al. Nano Lett. 2008, 8, 4283-4287) about electrical conductivity in ...
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50 views

Fermi level and conductivity

Can someone in a simple way explain me what the Fermi level is and what does it have to do with conductivity. My teacher said that Cu conducts electric current better than Al because of something in ...
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A conceptual question about Green's function's treatment of interaction

Here we have electron gas and some other stuff. We expand the Hamiltonian to the 1st order of one single harmonic oscillator's displacement $\vec{u}$. Its equilibrium position is at the origin. Then ...
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Phonon-phonon interaction

I have been told that phonon-phonon Interaction is an anharmonic effect so only arises if terms of third and higher order in the displacement of the ions the Hamiltonian for the nuclii is taken into ...
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55 views

Why is more intrinsic carriers bad for high temperature semiconductors?

I'm taking a solid state course, and is currently on the subject of dielectrics. In one of the sections, concerning "Impurities in Dielectrics" the books says: "Impurities can also be used to make ...
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219 views

Question about the quantization of lattice vibration (phonons)

In my syllabus about solid state physics they state that lattice vibration is quantized, analogous to the harmonic oscillator: $$E = (n+\frac{1}{2})\hbar\omega$$ So the lattice vibration has ...
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344 views

Probability of Different States - Canonical Ensemble - Partition Function

Consider a canonical ensemble of $N$ ideal gas atoms, which could have spin up or spin down. Why is it that the probability of finding the particle in a spin up state generally only involves the ...
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Holes in a P-type semiconductor under external force E

Basically in almost every semiconductor texts, there will be all these concepts concerning electrons, holes, dopants, fermi-levels. However, I have been always confused about the picture of hole ...
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540 views

Determining if a semiconductor is n-type, p-type or intrinsic

The probability that an energy state in the conduction band is occupied by an electron is 0.001. Would this semiconductor then be n-type, p-type, or intrinsic? Notation that I use: $E_F$ represents ...
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140 views

Connecting Fermi levels and band diagrams to potential diagrams?

I'm trying to make sense of how you can find the potential diagram given the band diagrams of a few adjacent materials. As a simple example, in semiconducting heterostructures, if you have sandwich ...
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48 views

Why can I see the 5D0 to 7F3 transition in the trivalent Eu?

According to the selection rules of the intra-configurational f-f transitions, if the J of the initial or final state is zero, a transition with $\Delta J = 3$ is forbidden by electrical dipole, ...
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What is the difference between lattice vectors and basis vectors?

Google has not been very useful in this regard. It seems no one has clearly defined terms and Kittel has too little on this.
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Ashcroft Mermin Solid State Physics Eq. 2.60ff

I'm trying to follow the steps in Eq. 2.60 of said book. What I cant seem to figure out is how to change the integration variables from 'k' to 'E', as they state. The equation is $$\int ...
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Mobility in semiconductors

Good afternoon everybody. I am reading on a book about semiconductor mobility. I have fully understood the definition, but I also noticed that often one talks about high or low mobility. My question ...
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Does anyone know the difference and relation between $k\cdot p$ method and tight binding (TB) method?

Among the methods of calculating energy bands for crystals, first-principles method is the most accurate. Besides first principles, two commonly used modeling methods are the $k\cdot p$ method and ...
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Energy band diagram of a system of Silicon Quantum dots

Suppose that we have a system of Silicon nanoparticles embedded in ZnO dielectric matrix. i'm thinking about how to construct the energy band structure of this system , suppose that we already have ...
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701 views

How is contact resistivity defined for a Schottky contact, or the Schottky barrier height for an ohmic contact?

Based on the transfer length method (TLM), one can accurately calculate the contact resistivity for an ohmic contact, by evaluating the absolute resistance measured through the test structure and ...
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82 views

Energy dispersion in graphene

Given that graphene has linear energy dispersion near the Fermi level and the dispersion is given by $E=\hbar \nu_F|\vec{K}|$, I would like to determine the density of states. I think it is equal to ...
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Frequency dependence of permittivity — why not monotonic?

I naively thought that most materials were transparent to radiation of frequencies above their plasma frequency, and opaque to radiation below it. The most intuitive (and analyzed lightly in ...
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Absorption of a gas into a solid

When a gas interacts with a (crystalline) solid, some scenarios may happen: scattering: gas atoms will not stick or penetrate (do not interact with the solid) Adsorption: gas atoms stick to the ...
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227 views

How to interpret band structures

I'm currently taking a Solid State Physics class, and is currently reading about the quantum mechanical description of solids. I then came across the following figure: It's supposed to be the band ...
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424 views

Partition Function for Two Level System

I have a system with $N_s$ sites and $N$ particles, such that $N_s >> N >> 1$. If a site has no particle, then there is zero energy associated with that site. The $N$ particles occupy the ...
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Why do excitonic absorptions have small bandwidth?

Below is an image of the optical density (proportional to the absorption coefficient) of KBr crystal at low temperature. Indicated at 6.6 ev and 7.7 eV are the absorption by excitons. As you can see, ...
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309 views

Derivation of Matrix Components of Hamiltonian in Tight Binding Method

Im currently struggling with the description of the tight binding method in the original paper by Slater and Koster from 1954 (where a free version of the paper can be found under this link). In ...
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216 views

valence bands in graphene

In Graphene, each carbon use 3 electrons to form sp2 bonding with neighboring, and in a unit cell, there are 2 carbon atoms, so at least these 6 electrons contribute to 6 valence bands. Then my ...
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Is this 2D structure triclinic?

The only rotation axis obvious to me is rotation by 360 degrees, the identity. Vertical mirror planes I've been dicing and cutting it through several planes and I still see none. Yet, the structure ...
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What are the rainbow and ladder approximations in a solid state physics context?

All references I find talk about quarks and gluons, where I have only very limited knowledge about. From it's name (rainbow) I guess it applies to fermions coupled to bosons and we're interested in ...
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181 views

I can't figure out crystal planes with negative intercepts

As seen above, I don't follow how you figure out those planes. It seems they're not using the origin labeled. I'm not really sure I understand spatially what's going on in the left figure so let's ...
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113 views

Electric current streamlines in induction cooking vessel

I am looking for a plot of the typical streamlines of the electric induced currents ("eddy currents") in a induction cooking vessel. How can one theoretically predict the streamlines? How is it ...
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74 views

Estimate the difference between two sets of atoms

I've been working on amorphous structures derived from a crystalline one (using MD) containing $N$ atoms. I want to prove that these structures are different and to quantify their "differentness". One ...
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152 views

Dispersion relation in continuum mechanics

I'm looking at the vibration of a solid having a lattice structure, they obey the following equation: $$\rho\partial_t^2u_i = C_{ijkl}\nabla_j\nabla_ku_{l}$$ with $u(\vec{x},t)$ the displacement to ...
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116 views

How creation of point defects in semiconductors is affected by strain?

When the effect of the strain on solids is discussed, normally the explanation is the following: increasing stress, first point defects created, then dislocations, then plastic deformation starts, ...
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Thomas-Fermi approximation and the dielectric function (+ small bit on graphene)

1) With the dielectric function, which is a function of wavenumber and frequency,how is it possible to take the limit of either to zero without changing the other one? I thought that frequency and ...
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Inhomogeneous Effective Mass in a 2D Lattice

Consider a tight-binding square lattice in 2D. This lattice has two different nearest neighbor tunneling rates along the x and y directions; call them $J_{x}$ and $J_{y}$. All longer range tunneling ...
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488 views

How robust is Kramers degeneracy in real material?

Kramers theorem rely on odd total number of electrons. In reality, total number of electrons is about 10^23. Can those electrons be so smart to count the total number precisely and decide to form ...
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What is the energy in eV between atoms in a typical solid state material?

Comps 2 question: What is the energy in eV between atoms in a typical solid state material ? Just rough estimate ? How is that related to the thermal energy that needs to be supplied in order to ...
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288 views

A question about definition of Fermi energy

Wikipedia states the definition of Fermi energy as for "a system of non-interacting fermions". If we have to assume free electrons in a solid behave this way before we are able to calculate Fermi ...
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What are the specific electronic properties that make an atom ferromagnetic versus simply paramagnetic?

As I understand it, paramagnetism is similar in its short-term effect to ferromagnetism (spins of the electrons line up with the magnetic field, etc.), though apparently the effect is weaker. What is ...
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Fourier analysis in crystallography

What is the best reference for an introduction to the use of Fourier analysis in crystallography?
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Effective mass in Aluminium lattice?

How do we calculate the effective mass of an electron in an Aluminium lattice? Is there any simple analytical way to work it out?
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Out-of-Plane Phonons

I am trying to derive the out-of-plane phonon dispersion relation for a membrane. As far as I can tell, one of the simplest ways to do so is with a Lagrangian of the form: ...
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How can one reasonably theoretically model polycrystalline materials?

Many techniques are taught in advanced solid state courses but they are almost all derived for perfectly crystalline materials. For example, band structure really only appears theoretically when you ...
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Electron degeneracy pressure

Why is it that in stars undergoing gravitational collapse electron degeneracy kicks in? Why couldn't the electrons form energy bands like in semiconductors?
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Does the Fermi sea have plane waves, or wave packets?

Consider a zero-temperature, one-dimensional crystal with allowed electron momenta $k_n = \frac{2\pi n}{L}$. Question: Which is the more correct way to think about the Fermi sea? Sharp plane ...
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Derivation of existence of energy band gap in semiconductor (solid State)

I am looking for both a mathematical and a physical reason for energy band gap in metals. For Physical reason, I was told that at each reciprocal lattice, you could have Bragg scattering, that would ...