Recent content by Abigale

Hi sure, in Ashcroft Mermin "Solid State Physics". Chapter 12 "Description of the Semiclassical Model" deals with the description of electrons by wave packets of Bloch Electrons. Would be nice if you could explain me if it also spreads...

Hi, to describe electronic transport and for example bloch oscillations, one uses a wave-packet build of bloch waves (with a band index n and an effective mass m*). Do these wave-packets of blochwaves also spread (disperse) over time?

Hi, I know that in an elecric field the potential energy ##E_{pot}## is equal to the potential ##V## times the charge ##E_{pot}=q V##. Here my problem: I know that the potential energy of a spring is ##E_{pot}= \frac{1}{2}kx^2##. In my theoretical physics book i read also that the potential is...

Okay thank you, makes sense. But I would write larger than ##>>2 \pi## to denote to get more than one revolution.

Hey, I read about charge carriers in semiconductors in a magnetic field. They write that for several revolutions ##\omega_c \tau >>1## holds. But I think for one revolution it is ##\omega_c \tau = 2 \pi##. (##\tau## is the scattering time) Why they do not write ##\omega_c \tau >> 2 \pi##...

I don't understand the notation ##dS_E##. $$d\bf{k} = k^2 sin\theta d\theta d\phi dk$$ $$ = dS_k dk_\bot $$ This means a surface-element times a radial distance-element perpendicular to the surface-element. Both in k-space. In the book instead of ##dS_k## the expression ##dS_E## is...

Hi, I am reading "An Introduction of Solid State Physics" from Ibach Lüth and don't understand the integration process. They write $$\sigma=\frac{e^2}{8\pi^3 \hbar} \int df_{E}dE \frac{v^2_x(\bf{k})}{v(\bf{k})} \tau(\bf{k}) \delta(E-E_F) $$ $$ = \int_{E=E_F}^{}df_{E}...

Hi, I read a chapter about the Heisenberg-model, and then something about the Hubbard-Model. The Heisenberg-model just shows, that neighbouring spins allign antiparallel if J<0. The Hubbard-Model says, that there is a hopping probability t and an Coulomb replsion, so that a material becomes...

Hi, I have read that Hund's rules are valid for Atoms with low z. Because the third Hund's rule is build of Russell-Saunders coupling. Can I still use the first and second Hund's rule for heavy atoms and jj-coupling( for the third rule)? Or how can I know the groundstate for an atom with large...

Hi guys, I consider the qm-derivation of the electronic states of hydrogen. There are two different derivations (I consider only the coulomb-force): 1) the proton is very heavy, so one can neglect the movement 2) the proton moves a little bit, so one uses the relative mass ##\mu## The...

Do someone knows what this dot "." means? I just know this notation [001]. Thank u Abigale

I am looking for a Book in which Solitons and Skyrmions are easy explained. I want to understand them for Solid State Physics. Thank U Abby

Hey guys, I regard a relativistic vector: $$ k^\mu =(k^0,k^1,k^2,k^3,)=(\frac{\omega_k}{c}, \vec{k} ) $$ What is |\vec{k}| of this vector? Is it the same as k^0? THX

Hey Guys, I regard two operators \Psi , \Phi , that don't commute. Does the product-rule, looks like that? $$\nabla (\Phi \Psi) = \Psi (\nabla \Phi) +\Phi (\nabla \Psi) $$ THX

I regard a Klein-Gordon-field. But for the Klein-Gordon-Field, the commutation-relation is $$ [\Psi^\dagger (x,t), \partial_t \Psi (x',t)] = -i\hbar\delta(r-r')$$ I even know that: $$ [\Psi^\dagger(x,t), \Psi (x',t)] = 0$$ and $$ [\partial_t\Psi^\dagger(x,t), \partial_t \Psi (x',t)] = 0$$ and...