TY  - JOUR
AU  - Volk, Christian
AU  - Neumann, Christoph
AU  - Kazarski, Sebastian
AU  - Fringes, Stefan
AU  - Engels, Stephan
AU  - Haupt, Federica
AU  - Müller, André
AU  - Stampfer, Christoph
TI  - Probing relaxation times in graphene quantum dots
JO  - Nature Communications
VL  - 4
SN  - 2041-1723
CY  - London
PB  - Nature Publishing Group
M1  - FZJ-2015-02801
SP  - 1753 
PY  - 2013
AB  - Graphene quantum dots are attractive candidates for solid-state quantum bits. In fact, the predicted weak spin-orbit and hyperfine interaction promise spin qubits with long coherence times. Graphene quantum dots have been extensively investigated with respect to their excitation spectrum, spin-filling sequence and electron-hole crossover. However, their relaxation dynamics remain largely unexplored. This is mainly due to challenges in device fabrication, in particular concerning the control of carrier confinement and the tunability of the tunnelling barriers, both crucial to experimentally investigate decoherence times. Here we report pulsed-gate transient current spectroscopy and relaxation time measurements of excited states in graphene quantum dots. This is achieved by an advanced device design that allows to individually tune the tunnelling barriers down to the low megahertz regime, while monitoring their asymmetry. Measuring transient currents through electronic excited states, we estimate a lower bound for charge relaxation times on the order of 60–100 ns.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000318872100110
C6  - pmid:23612294
DO  - DOI:10.1038/ncomms2738
UR  - https://juser.fz-juelich.de/record/189771
ER  -