Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 64: Quantum Wires: Transport
HL 64.10: Talk
Wednesday, March 16, 2011, 19:00–19:15, POT 251
Coupling molecular spin states by photon-assisted tunneling — •Lars Schreiber1, Floris Braakman1, Tristan Meunier1, Victor Calado1, Jeroen Danon2, Jake Taylor3, Werner Wegscheider4, and Lieven Vandersypen1 — 1Kavli Institute of Nanoscience, TU Delft, The Netherlands — 2Dahlem Center for Complex Quantum Systems, FU Berlin, Germany — 3Joint Quantum Institute of Standards and Technology, University of Maryland, USA — 4Solid State Physics Laboratory, ETH Zurich, Switzerland
Artificial molecules containing just one or two electrons provide a powerful platform for studies of orbital and spin quantum dynamics in nanoscale devices. A well-known example of these dynamics is tunneling of electrons between two coupled quantum dots triggered by microwave irradiation. So far, these tunneling processes have been treated as electric dipole-allowed spin-conserving events.
Here we report that microwaves can also excite tunneling transitions between states with different spin. In this work, we create an artificial hydrogen molecule by a gate-defined double quantum dot formed in a GaAs/(Al,Ga)As 2DEG. The dominant mechanism responsible for violation of spin conservation is the spin-orbit interaction. These transitions make it possible to perform detailed microwave spectroscopy of the molecular spin states and open up the possibility of realizing full quantum control of a two spin system via microwave excitation.