# Materials Physics on an Atomistic Scale 2

## Module PH2219

This module handbook serves to describe contents, learning outcome, methods and examination type as well as linking to current dates for courses and module examination in the respective sections.

### Module version of SS 2019 (current)

There are historic module descriptions of this module. A module description is valid until replaced by a newer one.

available module versions | |||
---|---|---|---|

SS 2019 | SS 2018 | SS 2017 | SS 2015 |

### Basic Information

PH2219 is a semester module in German or English language at Master’s level which is offered in summer semester.

This Module is included in the following catalogues within the study programs in physics.

- Specific catalogue of special courses for condensed matter physics
- Specific catalogue of special courses for Applied and Engineering Physics
- Complementary catalogue of special courses for nuclear, particle, and astrophysics
- Complementary catalogue of special courses for Biophysics

If not stated otherwise for export to a non-physics program the student workload is given in the following table.

Total workload | Contact hours | Credits (ECTS) |
---|---|---|

150 h | 30 h | 5 CP |

Responsible coordinator of the module PH2219 is Michael Leitner.

### Content, Learning Outcome and Preconditions

#### Content

This module is concerned with the arrangement and movement of atoms in solids. As these aspects determine to a large part the macroscopic properties of matter, their microscopical understanding is fundamental to, e.g., the tuning of materials for technological applications.

Going beyond the coverage of an introductory Solid State Physics course of Bachelor level and continuing the previous semester's course Materials Physics on an Atomistic Scale 1, here aspects of the oscillatory and diffusive dynamics in solids will be treated in detail:

- classical equations of motion -- harmonic approximation, consequence of translational symmetry, normal modes
- dispersions -- the Brillouin zone and special points, Born-von Karman model, consequences of point symmetries
- phonon densities of states -- van Hove singularities, vibrational thermodynamics, Einstein and Debye models
- effects beyond this setting -- anharmonicities, disorder
- fundamental concepts of diffusion -- random walk theory, connection to the diffusion equation, its solutions
- solid-state diffusion -- historical overview, transition state theory, Arrhenius behaviour, correlation functions, encounter model
- diffusion mechanisms -- in elementary systems and compounds

For all the above points both a general description of the relevant concepts as well as a motivation by microscopic models will be given, but also a quantitative discussion of their realization in typical systems.

#### Learning Outcome

Upon successful completion of the module, students are able to

- solve the equations of motion of atoms in a general crystal according to classical mechanics
- find their way about the Brillouin zones of the important Bravais lattices
- reproduce typical dispersion relations as well as recognize deviations from these typical cases
- use the Born-von Karman approach to model measured phonon frequencies
- understand the effect of symmetries on the normal modes
- understand how the dispersions lead to features of the density of states (i.e., van Hove singularities)
- employ model as well as actual phonon densities of states to compute thermodynamic quantities pertaining to vibrations
- understand how deviations from the ideal case lead to a broadening of the phonon dispersion
- derive the diffusion equation from the microscopic random walk
- apply the concepts of jump diffusion
- understand the characteristics of the possible diffusion mechanisms and thus, e.g., predict the effect of variations in compostion on the diffusivity

Generally, this modul intends to bring the students to a point where they can rationalize the results of theoretical or experimental investigations of pertinent aspects from the point of view of the present state of science, and thus to prepare them for original research.

#### Preconditions

No preconditions exceeding the admission requirements for the master degree program. Having participated in the course PH2218: Materials Physics on an Atomistic Scale 1 is beneficial, but no hard requirement.

### Courses, Learning and Teaching Methods and Literature

#### Courses and Schedule

Type | SWS | Title | Lecturer(s) | Dates |
---|---|---|---|---|

VO | 2 | Materials Physics on an Atomistic Scale 2 | Leitner, M. |
Wed, 10:00–12:00, PH-Cont. C.3203 |

#### Learning and Teaching Methods

In the lecture, the learning content is presented by blackboard writing and verbal lecturing, with a detailed discussion of the treated phenomena. Here active contributions from the students (comprehension questions) are invited. To consolidate the content, private study of the provided lecture script is indicated.

#### Media

Black board or beamer presentation. A lecture script will be provided, outlining the essential contents, but not superseding the detailed discussions given in the lecture.

#### Literature

Fundaments of solid-state physics:

- N. W. Ashcroft, N. D. Mermin: Solid State Physics
- H. Ibach, H. Lüth: Festkörperphysik
- Ch. Kittel: Introduction to Solid State Physics
- R. Gross, A. Marx: Festkörperphysik
- U. Rössler: Solid State Theory: An Introduction

Statistical physics:

- F. Schwabl: Statistische Mechanik

classical metal physics:

- G. Gottstein: Physikalische Grundlagen der Metallkunde
- P. Haasen: Physikalische Metallkunde

classical solid-state chemistry:

- J. Maier: Festkörper - Fehler und Funktion

atomic aspects of solids:

- M. T. Dove: Structure and Dynamics: An Atomic View of Materials

specialized aspects:

- W. Borchardt-Ott: Crystallography. An Introduction
- B. Fultz: Phase Transitions in Materials
- D. A. Porter, K. E. Easterling: Transformations in Metals and Alloys
- R. J. D. Tilley: Defects in Solids
- A. M. Kosevich: The Crystal Lattice. Phonons, Solitons, Dislocations, Superlattices

### Module Exam

#### Description of exams and course work

There will be an oral exam of about 25 minutes duration. Therein the achievement of the competencies given in section learning outcome is tested exemplarily at least to the given cognition level using discussions of the relevant concepts as well as typical realizations in solids.

For example an assignment in the exam might be:

- discussing the equations of motion in the harmonic approximation
- sketching typical phonon dispersion relations with discussion
- defining the concepts of migration energy and entropy
- explaining the encounter model

In the exam no learning aids are permitted.

#### Exam Repetition

The exam may be repeated at the end of the semester.