# Solid State Physics

## Postgraduate course

- ECTS credits
- 10
- Teaching semesters
- Autumn
- Course code
- PHYS208
- Number of semesters
- 1
- Teaching language
- English

## Course description

## Objectives and Content

Objectives:

The course gives an introduction to solid state physics, and wil enable the student to employ classical and quantum mechanical theories needed to understand the physical properties of solids. Emphasis is put on building models able to explain several different phenomena in the solid state.

The course conveys an understanding of how solid state physics has contributed to the existence of a number of important technological developments of importance in our lives now and in the future.

Content:

The course gives an introduction to the physics of the solid state. The first part considers bonds and crystal structure in solid matter. Mechanical properties are investigated and tied to specific bonds in solids. The interference pattern obtained by diffraction of waves by crystals reveals the lattice structure of the solid state. Particular emphasis is put on cubic and hexagonal crystals. Concepts such as the reciprocal lattice vector and the Brillouin zone are introduced. Lattice vibrations are analyzed, and the dispersion relationship is introduced to understand how the lattice vibrates. The Debye and Einstein models for heat capacity are covered to explain how the lattice energy changes with temperature. The course also covers heat conduction in solids, including Fouriers law for diffusive heat conduction, and also how to obtain the thermal conductivity of solid matter. Classical and quantum mechanical models for the electrical and heat conduction in free electron gases are studies, and simple models for electrons moving in periodic potentials allow one to understand the basic behavior of metals. Classification of band structure in conductors, semiconductors and insulators is given. The law of mass action and the transport of holes and electrons in semiconductors are analyzed, with an emphasis on the concept of effective mass. Schottky and PN-junctions are analyzed with respect to width and current-voltage characteristics. Applications of semiconductors, such as solar cells and light emitting diodes are also covered. The last part of the course covers magnetism and superconductivity. The concepts of dia, para and ferromagnetism are introduced, and one distinguishes between local (Curie) and band (Stoner) contributions to ferromagnetism. A short introduction to superconductivity is given.

## Learning Outcomes

On completion of the course

the student should have the following learning outcomes defined in terms of knowledge, skills and general competence:

Knowledge

The student is able to

- Explain mechanical properties of solid matter, and connect these to bond type.
- Explain how diffraction of electromagnetic waves on solid matter can be used to obtain lattice structure.
- Know the concept of `phonons¿, and how the dispersion relationship appears for different lattice structures.
- Explain how a lattice vibrates at finite temperature, and how these vibrations determine the heat capacity and conduction.
- Know the concept `density of states¿ in one, two and three dimensions.
- Explain simple theories for conduction of heat and electrical current in metals.
- Classify solid state matter according to their band gaps.
- Understand how electrons and holes behave in semiconductors, and explain how they conduct current.
- Explain and give simple models for Schottky and PN-junctions.
- Explain how ligh emitting diodes and solar cells work.
- Know the basic physics behind dia, para and ferromagnetism.
- Differentiate between local (Curie) and band (Stoner) contributions to ferromagnetism.
- Know what superconductivity is and qualitatively relate it to lattice vibrations and the density of state.

Skills

The student is able to

- Build models to understand the physical properties of solid matter.
- Critically evaluate the approximations needed to build models to understand the solid state.
- Write a short scientific paper on a published research work in solid state physics.

General competence

The student should

- Have insight into classical and quantum mechanical laws which can be applied to explain the properties of the solid state.
- Formulate and understand theories explaining the behavior of the solid state.
- Know the role of solid state physics in important technological developments.
- Read and be able to understand research articles in certain fields of physics.

## Semester of Instruction

## Required Previous Knowledge

## Forms of Assessment

*The forms of assessment are:*

*Compulsory excersises and class-room quizzes, 25 % of total grade.**Written examination (4 hours), 75% of total grade.*