So consider a 2D system with a circular potential and a spin-orbit interaction:
V(r) = V_0 \theta(r_0 - r) + c r_0 V_0 L_z S_z \delta(r-r_0)
where θ is step function.
So the operators Lz and Sz commute with the Hamiltonian are are therefore conserved quantities. For the same reasons...
Hello,
I am a post-doc in condensed matter theory (about to finish my 3rd year of my first post-doc) who is about to start applying for faculty positions. I am not sure who to use for my three references. Of course I will use my current adviser. Is it typical/ok to use my PhD adviser as well...
Hi,
Currently my wife and I are stuck in a two body problem with a separation of about 1500 miles. I have been looking for postdocs in her area (not many but a few more within a few hundred miles). My question is whether it is at all appropriate to mention the living situation and how getting...
Hi,
Have a question about images from a converging lens. I assume that the brightness of the (real) image projected on a screen depends upon the amount of light rays going through the lens - more rays -> brighter. So a larger lens should bring about a brighter image.
Ok, now let's go the...
Hi,
Really having a hard time finding conduction band offsets for semiconducting quantum wells - specifically GaAs/AlGaAs and CdTe/CdMgTe. I've heard 0.1 and 0.3 eV for AlGaAs and haven't seen anything on CdTe. Does anybody know of a reference where I could find these tabulated.
Thanks a...
Thanks for your reply.
I would like to determine the (average, I guess) velocity of electrons in the conduction band in the system I described. So I guess I would have to average k_F over the Boltzmann distribution since there will be a distribution of velocities.
Hi,
Ok, so let's say we have a non-degenerate n-type semiconductor such that the Fermi-level/chemical potential is somewhere in the bandgap (probably needs to be low temperature). Typically in a metal you would say that the Fermi velocity is \hbar k_F/m_e. But since the Fermi-energy is below...
Here's the issue I'm trying to wade through:
1. If you excite electrons from valence band to conduction band (with a laser say), you are out of thermodynamic equilibrium. In some recombination time, the system will go back to equilibrium. All well in good.
2. Now let us consider a very...
If you zap a n-type semicond. with a laser with energy at, say, the band gap, what happens to the donor electrons? For sake of argument, let's say we're at low temp. where the occupation of electrons on donors is high. I know technically, you should only get transitions at the energy of the...
Landau-Lif****z-Gilbert vs. Bloch
Could anyone elucidate on the difference between the phenomenology of the Landau-Lif****z-Gilbert equations and Bloch equations. When damping and relaxation are not included they have identical form. Are they the same thing? I've been learning about NMR related...
OK, I see. I guess the better question to ask is
When in general will you know that a solution will be independent of some parameter? For this case you made a change in variable and realized that the parameter in question will be an important part of the solutions. Is that something you would...
Wow. Thanks a lot for that. I've been banging my head for a while about that
A follow up question, if I may:
Will your reasoning be true whenever
\frac{d(\boldsymbol{m_1}+\boldsymbol{m_2})}{dt} \neq 0?
I'm not sure where to put this but I though DEQ would be a good start.
I have been dealing with the following differential equations:
\frac{d \mathbf{m_1}}{dt} = \gamma_1 \mathbf{m_1} \times \mathbf{B} - \frac{n_{2}}{\gamma_{cr}} \mathbf{m_1} +
\frac{n_1}{\gamma_{cr}} \mathbf{m_2}...
Ok, let's say you have n-type impurities in a semiconductor. So there is an equilibrium number of electrons in the conduction and impurity bands given by the temperature and the typical semiconductor statistics.
Now, you excite electrons from the valence to the conduction band. Here are my...