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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Why are Brillouin zones for graphene and monolayers of transition metal dichalcogenides the same?

The geometrical model of graphene is the flat honeycomb lattice, so the Brillouin zone is also flat honeycomb lattice. However, monolayer of transition metal dichalcogenides is not flat as it consists ...
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64 views

Simple Explanation of Kondo Effect

Does anyone have a simple explanation of the Kondo Effect? (i.e. a simple physical picture + maybe equations to think of?) My current understanding is this: If we consider an electron scattering ...
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14 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 ...
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22 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 ...
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41 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 ...
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Will using the WKB method for tunneling current give incorrect results for specifically low applied voltages?

I am simulating quantum tunneling through a rectangular potential barrier, as a function of applied voltage across the barrier as well as barrier thickness. I am following the theory from the book ...
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17 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 ...
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86 views

Does momentum space have a speed limit?

In ordinary $xyz$ space, the maximum velocity of propagation for mass-energy and/or information is $c$. So, my question: Is there also a maximum velocity of propagation in momentum ${p_x}{p_y}{p_z}$ ...
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170 views

Tight binding Hamiltonian for 2D finite dimensional lattice and nanowire

The Hamiltonian of a 1D lattice having finite $N$ atoms, (if we consider one basis per atom) is given by the following $N\times N$ matrix- Here $E$ is the onsite energy and $t$ is the hopping ...
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48 views

Magnitude of the band gap

In Kittels book on solid state physics (Introduction to solid state physics, p. 167, 8th ed.), he defines the band gap energy $E_g$ as $E_g = \int_0^1 U(x) [|\psi (+)|^2 - |\psi (-)|^2]$ where ...
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71 views

How to use Anderson's rule to construct band discontinuities in heterojunctions

I'm having some trouble in applying Anderson's rule to get a crude approximation for the band diagram of heterostructures. To make it more specific, I'm considering a donor-doped AlGaAs layer on top ...
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73 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 ...
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65 views

How do we get a 2DEG in a remote doped heterostructure?

I have a question regarding the way in which one often constructs a two-dimensional electron gas in heterostructures. I have a specific example in mind, although I believe this is quite a common way ...
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26 views

what is quasi-particle and its behaviour in solid?

I came across the term on several occasion while reading solid state physics and statistical mechanics. Didn't understand quite well. It'll be help if it's explained.
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41 views

Where does the lowered effective mass of electrons come from?

It is a known fact that electrons in the conduction band of a semiconductor can (in certain scenario's) be described as having an approximate parabolic dispersion relation of the form $E_c(k) = E_c + ...
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120 views

Why do we have heavy and light hole bands in semiconductors?

On the topic of the valence band of a semiconductor (in this example GaAS), it is the case that the valence band has some structure to it. As shown in the illustration below, we see that at the ...
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61 views

Relation between energy bands and Brillouin zones

In almost every book about solid state theory, electrons in a periodic potential are introduced and calculations for the dispersion relation $E(k)$ are presented. One obtains the usual pictures in ...
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31 views

Thermodynamic / Thermal Property

What is the definition for (i) Thermodynamic Property & (ii) Thermal Property? What are the subtle distinctions in the Thermodynamic Properties and Thermal Properties? ...
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53 views

Many-particle operators in the occupation number representation

I've read that if we have a many-particle operator in the coordinate representation which is the sum of identical one-particle operators operating, however, on different particles, like $\hat{Q} = ...
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41 views

What does a bucked honeycomb lattice mean?

I was going through some literature where they have mention about bucked honeycomb lattice, but I was unable to understand about the bucked honeycomb term.
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Can a material made of a heavier isotope of an element become harder or stronger?

I was wondering if any experiments have been done to measure if there is a change in the hardness or strength of a material made solely of a heavier isotope of an element which is a constituent of the ...
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56 views

Can the occupation of Floquet bands be calculated from the Keldysh Green's function?

A periodically driven band structure can be semiclassically described by Floquet theory, resulting in photon-dressed Floquet bands (non-equilibrium steady states). Usually, for non-equilibrium ...
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43 views

Effect of Particle Mass on Thermal Conductivity

Fouriers law of thermal conductivity is $$ \vec{q} = -k\nabla T $$ where $q$ is the heat flux, $k$ is the thermal conductivity. Mass does not seem to appear in the equation. So I'm wondering what ...
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How do phonon modes and other collective atom processes fit in with the Clausius-Mossotti relation?

The Clausius-Mossotti Relation relates the molecular polarizability of a chemical (that is, how much an electric field polarizes the molecule) to its dielectric constant, which determines its optical ...
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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 ...
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What happens to the electron density in a metal during an electric discharge?

Suppose we are able to see into a grain of metal at the boundary between the grain and air (perhaps along one of the faces of this cube): (Source: Wikimedia Commons.) This image does not show the ...
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58 views

Confusion with poles of single particle green's function / propagator

On p22 of "Green's Functions for Solid State Physicists" by Doniach and SondHeimer, there is the following definition: $$G^0(\omega)=\frac{1}{2M\Omega_0}\left( \frac{1}{\omega-\Omega_0+i\eta} - ...
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Diamagnetic materials are very rare, compared to paramagnetic and ferromagnetic materials, right? [closed]

For a material to be diamagnetic, it should have zero intrinsic magnetic dipole. Therefore, most materials are not diamagnetic, right?
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114 views

Dispersion of light in metals and the plasma frequency

I've been reading about the dielectric function and plasma oscillations recently and I encountered the following dispersion relation for EM waves in metals or in plasma (Is it correct to treat those ...
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34 views

What does it mean that an electron-hole pair is the fundamental unit of generation?

I wasn't certain to post this in chemistry or physics section. I was reading the wikipedia article on "Carrier generation and recombination" and in the second paragraph it says something that I ...
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97 views

What is a clear definition of vibrons?

What is a clear definition of vibrons? Vibrons are localized Phonons and I need more information about them. It is somewhat vague to me. Can you give some references, please?
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288 views

If s1 and s2 are the spin operators of two electrons, FInd out (s1 .s2) for the singlet and triplet states of hydrogen molecule [closed]

If s1 and s2 are the spin operators of two electrons, FI nd out (s1 .s2) for the singlet and triplet states of hydrogen molecule.
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52 views

Translating Electronic Bands back to first Brilluoin Zone

For phonons, I understand why we can translate everything back into the first Brillouin Zone: there is a minimum wavelength defined by two lattice sites. For electrons, which are delocalized, I see ...
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Diffusive or balistic? Spread of the wave packet when localized and extended states coexist

If the lattice is perfectly periodic, then the wave packet of a particle initially located on a site spreads balistically. Namely, its size increases linearly in time. Now, introduce disorder into ...
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How can we prove that each point (hkl) in the reciprocal lattice corresponds to a set of lattice planes (hkl) in the real space lattice?

In crystallography, we always speak about the direct and reciprocal lattice spaces. One property about these spaces in mentioned here, as follows: Each point (hkl) in the reciprocal lattice ...
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100 views

Photoelectric effect

Why the photoelectric effect is observed only for metals and not for non-metals? Isn't it possible for the photon to release an electron from a non-metal surface?
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semiconductors-band theory [duplicate]

How conduction happens with the conduction band electrons? I mean does the electrons which are responsible for the conduction of holes(by just moving from one atom to other) are those which are ...
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How to understand the simplified tight-binding representation on square lattice?

I have read a paper in this website:http://cmt.nbi.ku.dk/student_projects/bsc/Haider_Moradi_BSc_thesis.pdf I am curious about how to understand the simplified tight-binding representation on square ...
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cicumfernatial vector

Once a sheet of graphite is rolled up into a nanotube, the allowed values of k are constrained by the imposition of periodic boundary conditions along the circumferential direction. this periodic ...
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2answers
51 views

What is crater's influence on laser ablation?

In many laser ablation experiments (especially Pulsed Laser Deposition), target is moving to avoid crater formation. But I can't find any source that says why it is needed to avoid it. So why is ...
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45 views

What is the underlying transport mechanism of electron drift in metals?

The equations involving drift speed, mobility and conductivity, $v_d=\mu E$ and $\sigma=\mu e n$, treat electrons in a Newtonian way. This model works well in practice (at least in macro scale), but I ...
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23 views

Quasi-electron lifetime at Dirac (Weyl) point

I would like to know how one should calculate the electron lifetime with chemical potential at the Dirac point from Fermi Golden Rule: \begin{equation} ...
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54 views

What are the current carriers in a PN junction?

Imagine a PN junction in forward bias mode. The conventional current goes from the p-side to the n-side. However, as mobile holes move to the n-side, aren't there mobile electrons on the n-side which ...
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76 views

What is the difference between Fermi level and Fermi edge?

Just as in title: What is the difference between Fermi level and Fermi edge? My friend makes some research about XPS and he encountered this term. He knows what is Fermi level, but never heard about ...
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For the transition metals, how does counting the number of up-spins and down-spins still give you a non-integer magnetic moment?

The transition metals like Fe, Co and Ni have magnetic moments of 2.2, 1.7 and 0.6 Bohr magnetons, respectively. The band theory says that you get this when you calculate the density-of-states of the ...
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50 views

Photon absorption and emission in 2nd quantization

I am looking for models which describe the interaction of matter (lets take a 1D chain of atoms) with photons, especially the emission and absorption. I would love to see the derivation of models in ...
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2answers
107 views

Why do Weyl points come in pairs in solid state system?

Quoted from "Beyond Band Insulators: Topology of Semi-metals and Interacting Phases" by Turner and Vishwanath: In 3D lattice models, Weyl points always come in pairs of opposite helicity; this ...
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Are deforming force and stress always equal? If they are equal, then why does shape of the body get deformed?

If the deforming force is equal to the restoring force then there is no impact of the deforming force on the body. Then the shape of the body remains constant. How does the body deform, then?
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Numerically evaluating momentum sums

For many-body systems, calculations often involve momentum sums, which are ultimately evaluated numerically for a finite system size $N$. The larger $N$ is, the more accurate the results. Is there ...
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Difference between mechanical modes and phonons

As stated in this review article: Mechanical modes are long compared to the interatomic spacing. It is natural to make the distinction between nanomechanical modes and phonons: The former are ...