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
0answers
60 views

LOCAL Temperature Gradient and Stress

I'm investigating the thermo-migration failure mechanism in nanoscale ICs interconnects. Typically, a nano wire under thermal stress suffers from material/mass migration or void nucleation if it ...
1
vote
0answers
221 views

3D Density of states

I have the following dispersion relation: $$\epsilon(\vec{k})=\frac{\hbar}{2}\left(\frac{k_x^2}{m_1}+\frac{k_y^2}{m_2}-\frac{k_z^2}{m_3}\right)$$ (note the minus sign in the third term). And I am ...
1
vote
0answers
67 views

Bloch's theorem for Semi-Infinite Lattice

If we have a lattice Hamiltonian $$ \sum_{n'\in\mathbb{Z}}H_{n,n'}\psi_{n'} = E\psi_{n} \,\forall n\in\mathbb{Z} $$ such that $ H_{n,n'} = H_{n+q,n'+q}$ for some $q\in\mathbb{N}$ and for all ...
1
vote
0answers
63 views

Symmetry breaking and band gaps?

Can the discontinuity in the E-K dispersion relation of a periodic lattice (at the boundary of a Brillouin zone) be understood as a consequence of breaking continuous translation symmetry into ...
1
vote
0answers
39 views

Discrepancy in introducing Schottky barrier

I have a problem regarding introduction of Schottky barrier in metal-semiconductor junction. Because of this barrier the energies of conduction band vary discontinuously and hence the potential is ...
1
vote
0answers
761 views

The reciprocal lattice of HCP lattice

There is a very similar question here Reciprocal Lattice of a non-bravais lattice, but I don't fully understand the answer, and the question is now obsolete so I feel that I should ask it again. How ...
1
vote
0answers
26 views

Proton energy distribution after Si layer

I've been using SRIM to get an approximation of the energy distribution that a beam of monoenergetic incident ions will have after a thin layer of silicon. However, for my purposes it would be better ...
1
vote
0answers
101 views

Disclinations, dislocations, lattices, Displacement fields and scaling

I am looking up Frank, and Burger vectors and associated material on dislocation/disclination. It seems straightforward describing a lattice and what dislocation means. It is even possible to restrict ...
1
vote
0answers
178 views

Energy of an Electron in a One Dimensional Periodic Potential

First, we consider the time independent Schrodinger equation of the form: $$\bigg(-\frac{\hbar^2}{2m}\frac{d^2}{dx^2}+u(x) \bigg)\phi_A(x)=E_A\phi_A(x)$$ Where $u(x)$ is a potential created by a ...
1
vote
0answers
85 views

Why does inelastic X-ray scattering probe the longitudinal dielectric function as opposed to the transverse dielectric function?

Light is a transverse wave. Therefore, light in the optical range (i.e. visible light) couples to transverse collective excitations of a material when measuring the optical conductivity for instance. ...
1
vote
0answers
64 views

Physical, intuitive reason for divergence of dielectric constant at electronic percolation transition?

Several papers such as this (warning, PDF) and this (PDF again) talk about how, near the electronic percolation transition for a metallic 2D film, the real part of the dielectric constant diverges ...
1
vote
0answers
36 views

Most atoms have a nonzero magnetic moment, right?

This is my feeling. But more is different. If atoms form a solid, it is hard to say whether the solid will be ferromagnetic or not.
1
vote
0answers
33 views

Magnetic moment with external magnetic field on a lattice?

Consider a system in which atoms are located in a regular lattice, each atom having a spin $1/2$ and an associated intrinsic magnetic moment $\mu_0>0$. Assume that each atom interacts only weakly ...
1
vote
0answers
30 views

How to isolate and verify the source of optical absorption/effects?

This is similar to my other question, but not the same -- that one was about the energy ranges of various absorption mechanisms, and this one is more about experimental techniques to find them. Let's ...
1
vote
0answers
82 views

Should Brillouin zone be a continuous object rather than a discrete one in the thermodynamic limit?

For example, just consider a 1D atom chain with $N$ sites and lattice constant $a=2\pi$, under periodic boundary conditions, the crystal momentum reads as $k=\frac{n}{N}\frac{2\pi}{a}=\frac{n}{N}$, ...
1
vote
0answers
31 views

Interpreting current in a material as a Stark effect

I apologize if my question is silly but here it is. In the physics of atoms and molecules, we learn about the Stark effect which induces a splitting of degenerate energy levels into sub-energy levels ...
1
vote
0answers
61 views

Ion-neutralization processes and its energies

Ionization energies/Electron affinities are well mapped. I wonder about opposite processes... I imagine for anion the necessary energy will be equal to the electron affinity (energy released when ...
1
vote
0answers
229 views

Good introduction to many-body Green's function via path integral formulation?

Can anyone kindly provide any information on valuable references or books on this topic? It appears to be prevalent in 90s papers on High-Tc superconductivity or quantum Hall effect, especially in a ...
1
vote
0answers
109 views

Variational principle

In the LMTO method, the interstitial region is approximated by plane waves and the muffin tin region of the potential by solutions to the radial Schrodinger equation. In using the variational method ...
1
vote
0answers
24 views

Is there a way to quantify how similar a polycrystal should behave to a single crystal?

So in solid state classes we learned about phenomena like band structure and others arising from a periodic potential. Then we get to doing actual experiment and find out that materials being single ...
1
vote
0answers
61 views

Vacancy Generation / Annihilation Time (Relaxation Time)

Vacancy Generation/Annihilation Time, Recombination Time and Relaxation Time ($\tau$) are all synonymously used in atomic physics literatures. They're defined as the time that it takes for vacancies ...
1
vote
0answers
127 views

Bloch states at the zone boundary

How do I show that in 1D the Bloch states at the zone boundary $\left(k=\pm\frac{\pi}{a}\right)$ form standing waves? How is it clear, that there is a high- and a low energy state for a finite ...
1
vote
0answers
35 views

Simple examples for exchange and correlation

Is there an easy, in the best case intuitive, explanation of the difference of exchange and correlation? Is there a simple way to distinguish whether a certain contribution is due to exchange or ...
1
vote
0answers
183 views

Do I understand measurement of dispersion relation in a solid correctly?

I'm currently doing an introduction to solid state physics course and have a quick question about measurement of the dispersion relation of phonons in a solid: The way I understood it is the ...
1
vote
0answers
42 views

Is there a difference in binding energy between a regular material and a doped one?

Say Silicon and boron doped silicon. Would the doping affect the binding energy? Could I see this in an XPS spectra?
1
vote
0answers
276 views

More physical explanation of impurity energy levels in a doped semiconductor?

I'm reading about doped semiconductors in Ashcroft and Mermin. They tell you that when donor impurities are added to a semiconductor, their energy level $E_d$ is just slightly below the conduction ...
1
vote
0answers
294 views

Interpreting a Hamiltonian in terms of 'hopping' operators

I am having some trouble interpreting a Hamiltonian in terms of "hopping" operators. The Huckel model for nearest neighbour interaction in graphene is given by $$H=-t\sum_\vec{R}|\vec ...
1
vote
0answers
187 views

Average number of spin up particles

In a paramagnetic system, where $N = N_\uparrow + N_\downarrow$ is fixed, how does one calculate the average number of spin-up particles $\langle N_\uparrow \rangle$? You can assume we have the ...
1
vote
0answers
58 views

Long range repulsion in anomalous solids

As far as I know things like rocks, walls, rubber balls, polished tables etc. exert a short range repulsive force on other everyday objects that is responsible for hardness, softness, collisions, ...
1
vote
0answers
139 views

Is there a derivation of all possible Bravais lattices in 2D and 3D?

Do any of you know a (possibly elegant) derivation of all possible Bravais Lattice and the Crystallographic Group of Lattices in 2 and 3 dimensions? Group theory /abstract nonsense approaches are ...
1
vote
0answers
416 views

How to demonstrate that there are just 14 types of Bravais lattice?

Is it possible to demonstrate that there are just 14 types of Bravais lattice without the knowledge of group theory?
1
vote
0answers
84 views

When is the Fermi surface a surface of constant mean curvature?

Fermi surfaces are surfaces of constant energy in reciprocal space. They provide information about the properties of a material in solid state physics. Constant mean curvature surfaces are a superset ...
1
vote
0answers
125 views

What is the “center of gravity of a band”?

It seems there is a term called "center of gravity of a band" in solid state physics or chemistry which I'm confused about. Could anyone give a formal definition of the term or point to some reference ...
1
vote
0answers
197 views

Equal time displacement correlation functions and their physical interpretation?

Displacement correlation functions in question are within harmonic approximation and are derived for example in: A. Maradudin, Dynamical properties of solids 1, 1 (1974). Maradudin says about the ...
1
vote
0answers
138 views

Sommerfeld results & van Hove singularities

According to Sommerfeld the derivative of the density of states $g'(\varepsilon)$ apears in several thermodynamic quantities. Will this also be the case if one use the correct dispersion relation of ...
1
vote
0answers
47 views

Residual symmetries of the superposition of two fcc lattices

Fcc lattices are Bravais lattices and so are invariant under a set of discrete translations plus inversions over the 3 axis ($x\rightarrow -x$,$y\rightarrow -y$,$z\rightarrow -z$). When one superposes ...
1
vote
0answers
116 views

How to derive the divergence leading to Kohn anomalies?

I'm trying to understand the mathematical derivation given in the book "A Quantum Approach to Condensed Matter Physics" on page 215 (see 1), for explaining how the phonon-energy perturbed by ...
1
vote
0answers
153 views

Decomposition of elastic constants of a crystalline material

I have performed a calculation the tensor of elastic constants (or stiffness tensor) for a given crystalline material. From there, I calculated various elastic properties, such as Young’s modulus, ...
1
vote
0answers
433 views

Electron Fermi gas

My question is about 2-dimensional Fermi gas of electrons. What is magnetic susceptibility when $T<<T_F$ (where $T_F$ is Fermi Temperature) and, What is the ratio between Pauli and Curie ...
1
vote
0answers
611 views

Evaluation of band gap from transmittance

How can I evaluate the band gap of my ZnO thin film. Thickness=d=80 nm I’m aware of alpha=-1/d*log(T) But I can’t fit a line to my data. And: How can I smoothen my data on about 346 nm? Do you have ...
1
vote
0answers
459 views

Fermi level in disordered amorphous and/or organic semiconductors

So, the Fermi level in crystals is pretty easy to understand. Been using it and talking about it in terms of the highest occupied level forever. However, I'm now reading about disordered systems. A ...
0
votes
0answers
15 views

How to determine the basis of any crystal

In the following example, I have a rutile TiO2. Here the basis of O with respect to Ti is (0.3*x, 0.3*y, 0*z), where a,b,c are the lattice vectors. So in order to build a crystal, I need the basis and ...
0
votes
0answers
11 views

Conductive n-type material in pn junction

I'm interested in this question from the point of view of a solar cell. In a pn junction (example, p: CIGS, n: CdS), when the n-type material is very conductive, why will the junction not be ...
0
votes
0answers
19 views

Is it possible to derive the shape of the bending plates by use calculus of variations?

Of course the main idea to solve this problem is find the physical quantity which is have smallest or largest value. I’ve tried some, such as area of surfaces, But I think it can’t be a solution. Does ...
0
votes
0answers
7 views

type of photoluminescence depending on the FWHM

Depending on the FWHM of CdSe quantum dots, is it possible to estimate the type of dominant photoluminescence in question, as in excitonic luminescence is supposed to have a narrower spread than ...
0
votes
0answers
20 views

Do LEDs that require a higher forward voltage (at the same forward current) also use more power?

Why do some LEDs require a higher forward voltage than others for the same forward current? Is it defects, band-gap, etc? Does a higher forward voltage at the same current mean the LED is using more ...
0
votes
0answers
37 views

About the orthogonality catastrophe

I am reading the book of Mahan. In the section of orthogonality catastrophe, I can understand that the two N-particle Slater determinants ($\Phi_i$ and $\Phi_f$) are almost orthogonal as $N\rightarrow ...
0
votes
0answers
16 views

Can electroluminescence be theoretically used for RF communication?

I know that photon energy of radio frequency, 3 kHz (1.24e-11 eV) to 3GHz (1.24e-3 eV), is much smaller than the thermal energy $k_B T$ at 300K (25.8e-3 eV), which in turn is much smaller than typical ...
0
votes
0answers
41 views

Band gap origin

Many introductory books on solid state physics use images that I find confusing. For instance, one picture I see alot when reading about the band gap, is similar to this one: I understand that the ...
0
votes
0answers
11 views

compound bars in series

Compound bars 1 and 2 have lengths L1 and L2, areas A1 and A2, Young moduli E1, E2,thermal expansion coefficient a1 and a2. subjected to a change of temperature T. Two ends of the bar are fixed. The ...