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Haverford College
Departments of Physics and Astronomy
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Physics 322b12 – Solid State and Soft Matter Physics - Jerry Gollub

Understanding both conventional and soft materials using the principles of quantum and statistical physics. Crystallinity, lattice dynamics, conduction in metals, semiconductors and devices, and soft systems such as colloids, polymers, liquid crystals, and biological materials. Prerequisite: Physics 214b. Statistical physics is desirable. Typically offered yearly in alternation with Bryn Mawr.

Description

In this course we seek to understand the properties of both conventional and soft matter systems using the basic principles of quantum physics, statistical mechanics, and electromagnetism. The course will introduce you to important areas of contemporary science and technology, and help you integrate your previous work in physics. We will address questions such as these:

  • What are the possible geometries of perfect crystals, and how are these structures be determined experimentally?
  • How do we understand crystals that lack perfect translational order but come arbitrary close to repeating (quasi-crystals)?
  • Why are some solids metallic, while others are electrically insulating?
  • How does the crystalline structure affect the electronic states of metals and semiconductors?
  • How do the properties of semiconductors lead to useful devices?
  • What is the origin of superconductivity and why do these materials show macroscopic quantum behavior?
  • How can scattering experiments be used to study solids?
  • How does an applied magnetic field affect the electronic states in a solid?
  • How has solid state physics been affected in recent years by studies at the nanoscale, e.g. of carbon nanotubes?
  • How do we understand soft solids such as polymers, gels, liquid crystals, and biological materials, using ideas from statistical mechanics?

Prerequisites

This course is especially appropriate for students who have taken 214 and 303 and are interested in using physics to understand the materials that are important for technology and life.

Textbooks

For conventional solids, we’ll use Solid State Physics by Blakemore (Cambridge University Press, 1985). This book is more lucid than the classic texts by Kittel and by Ashcroft & Mermin (graduate level). I will provide a few other texts on Reserve. For soft matter topics we’ll use the excellent short text Soft Condensed Matter by R.A.L. Jones (Oxford University Press, 2002).

Format

Since we will be a small group, I plan to have students take turns (along with me) in making presentations on different topics. This should provide an excellent learning opportunity in making scientific presentations. I estimate that each student will be asked to make a presentation roughly every 2-3 weeks. To make time in our schedules for preparing presentations, the number of homework problems will be less than in some upper level courses.

Course Expectations

Regular attendance: Students are asked to attend all classes and tutorials. Absences should be limited to two, except for illness, or family need. If you are ill or expect to miss class due to special circumstances, a timely e-mail message to that effect is appreciated. Especially in a small course, each person counts.

Preparation: Please come to class prepared to participate. Classes should be highly interactive, with lots of conversation. When you are leading a class, careful preparation is needed. (I can assist you.)

Homework: There will be some homework, maybe 3-4 problems per week, less than in some courses like 303. We will discuss the HW in Tutorials (at the regular class time) before they are due. Probably the class will not be large enough to have tutorial groups. While we’ll need a leader for each problem, we’ll also need everyone to pose questions and chime in.

Exams: In this course, your major responsibility will be to prepare presentations on different topics. Therefore, we’ll have only a final exam, no midterm.

Short Paper: You will be asked to write a short paper on a library investigation of a topic of your choice relevant to the course.

Grading

Grading philosophy: I will look for effort, engagement, and mastery on an individual basis. The performance of one student does not affect the grades of others. Historically, the average grade of students in upper level courses I have taught is around 3.3 – 3.7 (B+ to A- on a letter grade scale), but each class is different.

Weights: The following weights will be applied to the various components.

  • Homework20%
  • Short Paper25%
  • Class Presentations25%
  • Final Exam30%

Homework: Please note that clarity and the generous use of explanatory prose is expected.

Late assignments: Try to do them on time. A late penalty of 3% per day may be applied as encouragement. There is one free extension. Please let me know when you decide to take it.

Honor code

You are encouraged to discuss homework with each other but your final written work should be your own, though it may be influenced by prior discussion. Two assignments or exams that have substantially identical wording or equations in one paragraph or more would not meet this expectation. Sources (e.g. books) or other assistance should be acknowledged.

Interactions

Electronic mail (sent to jgollub) is always welcome and will generally be answered between 2 and 6 p.m. on weekdays and often on Sunday afternoon or evening.

Phone: You may phone my office at 896-1196. Please leave a message if I'm not there, along with a suggested time in the evening when I can return your call. It’s fine to call me at home (649-4159) from 9 to 11 p.m. occasionally, Sunday through Thursday.

Office: I will be very happy to speak with you immediately after any class period (at 11:30 a.m.) , or to arrange an appointment at a mutually agreeable time. Please also do not feel shy about dropping in or about phoning. If busy, I'll suggest another time.

I look forward to working with you. I appreciate your feedback, and urge you to communicate any concerns without delay.

Outline (1-2 classes per topic). Students can affect the outline.

Crystallinity

  • Atomic binding
  • Symmetries operations
  • Crystal structures
  • Crystal diffraction
  • Reciprocal space
  • Defects

Lattice Dynamics

  • Vibrational modes of lattices
  • Vibrations when there is a “basis”
  • Phonon statistics

Electrons in metals

  • Classical free electron theory
  • Quantum theory of conduction
  • Band theory
  • Electronic dynamics in energy bands
  • Superconductivity

Semiconductors

  • Electron and hole statistics
  • Electron transport in semiconductors
  • Band shapes
  • Excess carriers
  • Useful devices

Soft Matter

  • Introduction
  • Phase transitions
  • Colloidal dispersions
  • Polymers
  • Gelation
  • Liquid crystals
  • Self assembly
  • Biological materials