Magnetism and Spin Phenomena in Low Dimensional Electronic Systems

This module gives an introduction to magnetism and spin-phenomena in semiconductor-based low-dimensional electron systems. Following a recapitulation of some basics of magnetism, electronic band structures are discussed with special regard to the influence of spin-orbit coupling. Magnetic quantum oscillations in two-dimensional electron systems are treated in detail. The impact of the spin degree of freedom, of the many-body interaction and of the dimensionality of the charge carrier systems on the energy spectrum in a magnetic field is considered and explained within theoretical models. Relevant aspects of semiconductor spintronics like injection and detection of spin-polarized currents, spin coherence and spin relaxation, optical spin orientation and electrical manipulation of spin states via spin-orbit coupling are discussed. In the last past of the lecture, experimental milestones in semiconductor spintronics and quantum oscillations experiments determining relevant spin-orbit-coupling parameters are illustrated.

After successful participation in this module the student is able to:

1. describe the impact of spin-orbit coupling on the electronic states in semiconductors
2. to comprehend and explain orbital and spin-related effects on the magnetism of low-dimensional electron systems
3. evaluate the influence of disorder, temperature, many-body effects, choice of material and dimensionality on the electronic spectrum
4. to name and explain basic physical aspects of modern semiconductor spintronics like electrical and optical spin injection, manipulation and detection
5. differentiate between different spin-dependent scattering mechanisms
6. to understand and explain properties of magnetic semiconductors

Keine Vorkenntnisse nötig, die über die Zulassungsvoraussetzungen zum Masterstudium hinausgehen.

lecture, beamer presentation, board work

lecture script, accompanying internet site, complementary literature

1. S. Blundell: Magnetism in Condensed Matter (Oxford University Press, 2001)
2. Y. Singleton: Band Theory and Electronic Properties of Solids (Oxford University Press, 2001)
3. P.Y. Yu: Fundamentals of Semiconductors (Springer Berlin, 1996)
4. M.I. Dyakonov (Ed.): Spin Physics in Semiconductors (Springer Series in Solid-State Sciences 157, 2008)
5. Stefan Blügel, Daniel Bürgler, Markus Morgenstern, Claus M. Schneider, Rainer Waser (Eds.): Spintronics - From GMR to Quantum Information, (Schriften des Forschungszentrums Jülich Reihe Schlüsseltechnologien / Key Technologies Band/Volume 10)
6. Kronmüller H., Parkin S.S.P. (Eds.): Handbook of Magnetism and Advanced Magnetic Materials, Vols. 1-5 (Wiley, Chichester, 2007)

There will be an oral exam of 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 comprehension questions and sample calculations.

For example an assignment in the exam might be:

• Describe the influence of spin-orbit coupling on the electronic band structure in semiconductors
• Explain the appearance of magnetic quantum oscillations in low-dimensional electron systems
• Discuss the influence of disorder, temperature, many-body effects, material choice and dimensionality on the magnetic quantum oscillations
• Name spin-dependent scattering mechanisms in semiconductors