Kai Sun

University of Michigan, Ann Arbor

Plan for today

Overview of solid state physics Course Syllabus

What is this course about?

Systems under study: Solids • What is a solid? • Solid is different from other states of matter by its

shear modulus (ability to resist the change of shape) • Examples: metal, stone, wood, plastics, glass, …

Methods: All we have learned! • Quantum mechanics • Electromagnetism • Statistical mechanics and thermodynamics • Mechanics • Various math tools (Fourier transform, eigen-problem, …)

How is this course different from others?

Previous courses (e.g., Mechanics, QM, E&M, Stat Mech,…) • Start from a few fundamental laws • Derive theorems from these laws • Verify the agreement with experiments

Solid state physics • Start by looking at real materials • Think about which laws/theorems apply here

(important step: make simplifications and approximations!) • Evaluate our model and think about how to do better • Prepares you for future research

What will we learn?

What are nucleons doing in a solid? What are electrons doing in a solid? What are spins doing in a solid? Topics of modern condensed matter Effects of disorder

What are nucleons doing in a solid?

Picture from wikipedia.com

Simple solids: crystals (we mostly deal with in this course)

Noncrystalline solids

(much more complicated to characterize)

• Why they exhibit such orders?

• How many types of crystal structures are there?

Nucleons don’t stay still at lattice sites!

At finite temperature: thermal fluctuations

• Vibrate around their equilibrium positions

• Interact with each other

Result: waves

Corresponding particles: Phonons

What are electrons doing in a solid?

Why are there two types of solids: conductors and insulators?

It is a quantum phenomenon

Superconductivity

The search for the best conductor: superconductor

Perfect conductivity (no resistance)

Picture from wikipedia.com

Superconductivity

Meissner effect: B=0

Magnetic levitation

Picture from wikipedia.com

Maglev train

Shanghai Maglev Train Mechanical force Magnetic force

No contact No friction Low noise High speed (300m/h)

What are spins doing in a solid?

Ferromagnetism 𝑀 ≠ 0

They play a very important role in the magnetism of solids

Paramagnetism 𝑀 = 0

𝑚

Magnetism (more exotic examples)

Anti-ferromagnetic:

Spin liquid:

Topics of modern condensed matter

Topological insulator

Conductor

Topological insulator: insulator inside but metal outside

Topological insulator

Why? Answer: Topology of the quantum wavefunction

Topics of modern condensed matter

Two different scales

High temperature superconductivity

Course Syllabus

Instructor: Prof. Kai Sun Email: sunkai@umich.edu Phone: 734-764-0730 Office: 2245 Randall Course Homepage: http://www-personal.umich.edu/~sunkai/teaching/Winter_2013/phys463.html

Time and place Time: 8:30-10:00 am, Tuesdays and Thursdays Place: 335 West Hall Office hour: TBD (2245 Randall)

Course Syllabus

Textbook • Required textbook: Kittel, “Introduction to Solid State Physics” , 8th ed. • Additional reference (not required): Ashcroft and Mermin, Solid State Physics • Both books are on reserve at the library

Prerequisite PHYSICS 453 or equivalent

Problem Sets bi-weekly

Course work and grading

Course grade will be based on • Problem set: 20% • Final Presentation: 20%

You will form teams of up to 3 members. Each team will give a 15 minute presentation on a topic you choose, illustrating an application of solid state physics.

• Midterm: 30% • Final: 30%