Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 29: Quantum dots: Optical properties II

HL 29.12: Vortrag

Mittwoch, 25. März 2009, 12:45–13:00, BEY 154

Optical spin control in charged quantum dots with a single Mn atom — •Giselmar Hemmert¹, Doris E. Reiter¹, Vollrath Martin Axt², and Tilmann Kuhn¹ — ¹Institut für Festkörpertheorie, WWU Münster, Wilhelm-Klemm-Str. 10, 48149 Münster — ²Institut für Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth

In semiconductor quantum dots spins bear good prospects as basic elements for new quantum hardware such as quantum bits. In a single quantum dot containing a single Mn atom charged by an electron (hole) the excitation by laser light causes the formation of a trion complex, i.e. a positively or negatively charged exciton. The trion spin, like the carrier spin in the non-excited state, is coupled to the Mn spin via the exchange interaction. This coupling allows for the manipulation of the optically not directly accessible Mn spin via spin flip processes of either the electron (hole) or the trion and thus ultimately for the manipulation of the Mn spin by laser light. We consider a charged CdTe quantum dot doped with a single Mn atom and focus on electron and light hole processes as heavy holes do not induce spin flips. Starting from a well defined initial state we show that the six Mn spin states can be set by a series of ultrashort laser pulses. Thus besides the electron (hole)/trion spin also the Mn spin may be used as a basis for controlled operations in the field of spintronics.