Photocurrents and phase coherent transport in InAs:Mn

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Within this project we plan to explore spin-orbit interaction and topological quantum effects in novel. InAs:Mn heterostructures containing a two-dimensional hole gas (2DHG). In addition to the large spin-orbit coupling the material is characterized by exchange coupling between the two-dimensional holes and the built in Mn ions with spin 5/2. The project involves the growth and optimization of InAs:Mn heterostructures, the characterization of spin-orbit interaction (i.e. the separation of Rashbaand Dresselhaus spin-orbit coupling strength) by means of terahertz induced photocurrents and the systematic investigation of quantum interference effects which stem from geometric phases. For this purpose nanoscale ring structures will be made out of InAs:Mn in which the Rashba coefficient α can be tuned by means of an applied electric field. While spin orbit interaction gives rise to additional phases like the Aharonov-Anandan and the Aharonov-Casher phase it is an open issue how exchange coupling in this systems alters these phase coherent phenomena. Within this project we aim at a detailed understanding of the InAs:Mn two-dimensional hole system and a deeper insight into the role of exchange interaction for topological quantum effects.