Higginbotham, Andrew P4; Larsen, Thorvald Wadum4; Yao, Jun2; Yan, Hao3; Lieber, Charles M2; Marcus, Charles M4; Kuemmeth, Ferdinand4
1 Condensed Matter Physics, The Niels Bohr Institute, Faculty of Science, Københavns Universitet2 unknown3 Department of Chemistry4 Condensed Matter Physics, The Niels Bohr Institute, Faculty of Science, Københavns Universitet
Relaxation and dephasing of hole spins are measured in a gate-defined Ge/Si nanowire double quantum dot using a fast pulsed-gate method and dispersive readout. An inhomogeneous dephasing time T2(*)≈ 0.18 μs exceeds corresponding measurements in III-V semiconductors by more than an order of magnitude, as expected for predominately nuclear-spin-free materials. Dephasing is observed to be exponential in time, indicating the presence of a broadband noise source, rather than Gaussian, previously seen in systems with nuclear-spin-dominated dephasing.