PHZ 6426 - SOLID STATE PHYSICS I - FALL 2008
NEWS & ANNOUNCEMENTS
December 13:
I have scored your HW9 assignment. The answers are posted as of Monday morning 12/15 early. Two remarks:
1. In 17.1(b) and 17.2(b) (deriving the Hartree and Hartree-Fock equations) I had to deduct 5 points for many of you. The d psi_i and d psi*_i infinitesimals are independent in variational calculus. You can see that if you recognize that complex numbers/functions are defined as the sum of a real and an imaginary number/function. The two equations you end up with are each other's complex conjugates though, and with the eigen energies being real (since the hamiltonian is hermitian) they are essentially the same equation.
2. In 17.5, strictly speaking, the first-order wave function expression (17.79) should exclude the k=k' term, per the definition of a first-order form. However, I showed in the posted answer that including this term does not contribute anything, courtesy of the pseudo-continuous k integration (thanks to the thermodynamic limit N->\infinity). I did not deduct points if you (as well as Ashcroft and Mermin) missed that subtlety.
See you at the exam, Dec 16, 10a at 1011 NPB!
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December 9:
1. *The final exam *will cover Chs.12,13,17,22,23. I have 'composed' four questions associated with these Chapters. To some extent each question covers the material in at least two chapters.In other words, you should be prepared to study all chapters to the same depth of understanding.
The questions are broken down into many sub-questions, so even if you do not know the answers to all you can get a 'decent' score. Almost all questions are qualitative in nature, and require little or no calculations, just good conceptual understanding (with one exception). If you keep the answers short (and correct ones are) you will have ample time in two hours to finish the exam.
As to the time on December 16, I propose that you all come to our room 1011 NPB at 10:00a. We will either use that room (if not in use for another exam) or we occupy another one in the building. We expect many to choose from.
2. *Class Paper. *There are still a few of you who have not handed in BOTH a paper and an e-copy of your project paper. If you want to get credit for it, you have until W 12/10, 5p to hand it to me. I am sorry, but after that time I will ignore your submission.
3. *HW9. *Do not forget to hand in your HW9 this Friday, 12/12 by 5p. Answers will be posted hopefully that day, if not then on M12/15.
4. *Final Grade. *I hope to have your final grade available shortly after December 16, but not before December 18. The scored final exams and class papers will be in the box outside my office. The correct answers will be posted as usual.
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December 1: First, there are still six people to come with a choice of a topic for their class paper. Do not forget, the deadline for submission is December 8, a week from now! When you hand me your class papers, send me also an electronic copy. After the end of the semester I will send copies of all papers to each of you .
Second, we will keep the Final Exam date for most of you (~17) for December 16. I will try to find a better time than the 7:30-9:30a slot. One of you will take it on December 11, and four on December 12, according to my count this morning. Please come to me to set precise times and places.
Third, although for the final exam you should be prepared to know all the material we covered in class this semester (since it all hangs together), questions will be largely related to Chs. 12,13,17, 22,23 (thus no tight binding (Ch.10) or cohesive energy (Ch.20)).
Fourth, I will have to go pretty fast through Chapters 22 and 23. Yet, I expect you to study it all to the point of understanding it. See me at any time (even outside office hours) to make sure of that. It is best to send an e-mail with requests for some day(s), with dates and times for mee to choose from. I will respond with my choices.
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November 21: I have added two sets of answers to problems with Chs. 20 and 22. These are just for your help and exercises in studying these Chapters, not to be handed in for Homework.
As announced earlier, we will close out this semester with Ch.20-23. I will very soon give you a summary what subjects, Chapters etc. I will cover in the final exam.
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November 4: We will skip the last part of A&M's Ch. 12:"High-Field Hall Effect and Magnetoresistance".
Correspondingly, we will drop Problem 12.4 from HW8. The max scores for the Chapter 12 problems is now: 12.1(20),12.2(40), 12.3(40).
See "Homework Assignment" link: there was an error in HW9, problem 17.5(20), was accidentally 'assigned' twice!
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October 29: Starting this Friday 10/31 we enter the 'homestretch' of our course, with fifteen more lectures to go. I have decided to cover Chs. 12, 13, 17, (21),22,23. That's quite a lot of material, and I plan to give three lectures per chapter. It is likely that I can not cover all the material to the same depth. Therefore I expect you to bear with me, and do self-study on the way. Some topics I will simply skip, and I will let you know whether I expect you to study them for the final exam.
I also must urge you again to come to me with your choice of Class paper topic. You can discuss it with me after class, in my office hour, or write me an e-mail (preferably) with a bit of an outline what you want to do. The paper is due December 8, so do not delay to much longer!
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October 27: You can postpone handing in the solutions to Homework 6 until Friday October 31, 5pm, upon the request from several of you having to prepare for a particle physics test on October 29.
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October 16: I have decided that we will not have class next week (M10/20 and W10/22) at all. F10/24 is a Holiday because of Homecoming.
Instead I expect you to perform self-study as follows:
1. the remainder of Chapter 9 after Friday 10/17 class (3D band structure, geometric structure factor in potential)
2. Chapter 10 until Eq.(10.15)
If you have any questions, send by e-mail, and will answer, or wait until the week after for Office hour etc. We will meet again M10/27.
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October 7: I have graded the First Midterm, and the solutions are also posted. The average is 67.4, not bad for a first test on this topic! Please consult my answers, and (hopefully) convince yourself that I got the answers right, that things are indeed simpler than some of you thought, and learn from your mistakes.
See you in class tomorrow!
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You got high marks for the second homework assignment. And that not only because most of you got the answers right, it was a lot of work because there were many details.
With regard to the polarization question for Problem 1.5(f), both on the metal and the vacuum sides of the surface (i.e., z>0 and z<0, respectively) the polarizations of the surface plasmon are circular at \omega=\omega/\sqrt{2}, with a phase shift across the surface. Look carefully at my answer.
Also, notice there is a forbidden region for q^2c2 versus \omega2 values between \omega_p2/2 and \omega_p2.
If you have any trouble with my grading, come and see me.