6.730  Physics for Solid State Applications

Addendum: Link for 2008 Final; Typo in Lect 30 on Moment Equations

Two more points:

1) The link for the 2008 Final Exam is:

http://stellar.mit.edu/S/course/6/sp11/6.730/courseMaterial/topics/topic1/studyMaterial/Final2008rev/Final2008rev.pdf

2) Speaking of understanding what the various terms signify in Boltzmann's Equation or its Moment Equations, there's a pertinent typo in Lecture 30. First, here's the link:

http://stellar.mit.edu/S/course/6/sp11/6.730/courseMaterial/topics/topic3/lectureNotes/Lecture_30_[Compatibility_Mode]/Lecture_30_[Compatibility_Mode].pdf

And now here's the typo. It is on the top slide of page 7 in the definition of the matrix elements W_{ij} in the kinetic energy density tensor \overline{\overline{W}} (Note: If you're scared of the fancy word "tensor", then note \overline{\overline{W}} is just a D x D matrix in D dimensions).

The typo specifically is the omission of thermodynamic averaging brackets "‹ ›" around k_i k_j. Thus the correct definition of the matrix elements W_{ij} is

W_{ij} = \frac{\hbar^2}{2 m*} ‹ k_i k_j ›

where ‹ k_i k_j › = thermodynamic average of (k_i k_j), that is the integral over all k vectors of the product [k_i k_j f(r,k,t)], where f is the semiclassical distribution function used in Boltzmann's equation (i.e., the probability of having an electron at "position" r with for-all-intents-and-purposes-free-particle-like momentum \hbar k at time t.

(Note: The lecture notes do correctly go through the argument of how to calculate these thermodynamic averages ‹k_i k_j› in the Boltzmann limit where the carriers are treatable like a classical ideal gas---see bottom of page 9 and top of page 10... it's just the notes don't always make it explicit that we're dealing with thermodynamic averages by consistently using brackets.)

Good luck,

Bill

Announced on 13 May 2011  6:35  p.m. by William M Kaminsky

2008 Final Exam available online; Review sessions Sunday 1-3 PM, Monday 8-9 *AM* (Your exa

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A. For those who didn't get a hardcopy, a PDF of the 2008 Final Exam is available online.

Since parts of final exams do get recycled from year to year, sorry, we don't ever post solutions to the final exams.

**On that note, the structure of the final exam this year is very close to that of this 2008 exam. And by very close we mean you can indeed expect

1) 10 points worth of multiple-choice/short answer general knowledge

2) 20-25 points worth of phonon (PSet 4) type material, certainly involving writing down and/or manipulating some tractable reduced dynamical matrix at some point and calculating phonon specific heats and/or the speeds of sound associated with different phonon modes)

3) 20-25 points worth of band structure calculating material (PSet 5), certainly involving writing down and/or manipulating some tractable reduced Hamiltonian matrix at some point and determining whether the resulting band structure at a given number of electrons per unit cell is a metal or a semiconductor)

4) 20-25 points worth of band structure of silicon type material (PSet 6): conduction band ellipsoids, light holes, heavy holes, conductivity and density-of-states effective masses, confinement potentials yielding 1D or 2D electron gases)

5) 20-25 points worth of PSet 7 and 8 material (simple intuitive arguments about how rate equations scale with reactant concentrations, acoustic deformation potential scattering -- with an eye toward the "big picture" and physical intuition about what its components signify as opposed to the nitty-gritty of calculating integrals in full, Boltzmann's equation and its 0th, 1st, and/or 2nd moment equations---again with an eye to physical intuition about what their components signify as opposed to nitty-gritty solution of partial differential equations)

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B. There remaining review sessions are:

-- Sun 5/15: Bill 1:00-3:00 in 26-322 (if available, else 26-168, our Mon/Wed usual classroom)

-- Mon 5/16: Bill 8:00-9:00*AM* in 32-124 (i.e., the room in the Stata Center where you're having YOUR FINAL from 9AM - Noon)
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C. Feel free to email any questions you have in the interim.

Good luck,

Bill

Announced on 13 May 2011  5:54  p.m. by William M Kaminsky

REMINDER: Review 1-3 today in 26-322. (All your psets will be corrected.)

1) REMINDER: I'm running a review session from 1-3pm today in 26-322 (our normal Friday classroom). I'm intending this review to be question driven, and I'd prefer questions to be slightly more thought out than "What's the answer to question X on the 2008 final?" [not necessarily much more thought out, but slightly more thought out. For example, question asking strategies like the following one from The Simpsons are advised :)
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Jewish Man: Rabbi, should I buy a Chrysler?

Rabbi Krustofski [Krusty the Clown's father]: Could you rephrase that as an ethical question?

Jewish Man: Um... is it right to buy a Chrysler?

Rabbi Krustofski: Oh, yes. For great is the car with power steering and dyna-flow suspension.

from "Like Father, Like Clown" Episode 8F05 (Season 3, Number 6)
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2) At this session, I'll also have all your psets corrected for you to pick up.

All the best,

Bill

Announced on 13 May 2011  3:45  a.m. by William M Kaminsky

Formula sheets for the final

Announced on 11 May 2011  5:21  p.m. by William M Kaminsky

Office Hours (Lots of 'em); SolSet 7 posted

1) Solution Set 7 has been posted to Stellar.

2) Prof. Orlando and I are having lots of office hours this week:

Tue 5/10: Prof. Orlando 4:30-5:30 in 13-3006

Wed 5/11: Prof. Orlando 3:30-5:30 in 13-3006

Thu 5/12: Prof. Orlando 1:00-3:00 in 13-3006

Fri 5/13: Bill 1:00-3:00 in 26-322 (our usual Fri classroom)

Sat 5/14: -- Nothing presently--

Sun 5/15: Bill 1:00-3:00 in 26-322 (if available, else 26-168, our Mon/Wed usual classroom)

Mon 5/16: Bill 8:00-9:00*AM* in 32-124 (i.e., the room in the Stata Center where you're having YOUR FINAL from 9AM - Noon)

Good luck, and please, please email any questions you're pondering to Prof. Orlando and myself, because if you're asking them, then probably others in the class are too and it helps to have a list.

Announced on 09 May 2011  5:01  p.m. by William M Kaminsky