Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 75: Quantum Dots: Transport Properties II

HL 75.5: Talk

Thursday, March 23, 2017, 16:00–16:15, POT 151

Determining tunneling times in Ge hut wires via single-shot measurements — •Lada Vukušić, Josip Kukučka, Hannes Watzinger, Elisabeth Lausecker, and Georgios Katsaros — IST Austria

Group IV semiconductors are an attractive platform for spin qubits, with electron spin coherence times in isotopically purified Si exceeding 0.5 s [1]. Nevertheless, for fast gate manipulation, holes should be more suitable due to the stronger spin-orbit coupling. Purely HH states have been predicted to show long dephasing and, under certain conditions, relaxation times [2]. Here we work with Ge hut wires, a system which has been recently shown to confine almost purely HH states [3]. For determining the hole-spin relaxation time, a charge sensor is needed. Recently, we have realized for the first time charge sensing in Ge hut wires, which is based on both capacitive and tunnel coupling between two hut wires [4]. For achieving a fast readout, the charge sensor has been connected to a radio frequency reflectometry setup [5]. With this configuration we have measured the single-hole tunnel time between the two quantum dots to be about 10 us, which is two orders of magnitude smaller than the predicted spin relaxation time [6]. Thus, it is perfectly suitable for performing spin readout measurements.

[1] J. T. Muhonen et al., Nature Nano 9, 986 (2014); [2] D. V. Bulaev and D. Loss, PRL 95, 076805 (2005); [3] H. Watzinger et al., Nano Letters 16, 6879 (2016); [4] A. Morello et al., Nature 467 (2010); [5] N. Ares et al., PR Applied 5, 034011 (2016); [6] A. F. Zinov'eva et. al., Jetp Lett. 82, 302 (2005);