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R. G. Herb Condensed Matter Seminar
Charge sensing and excited state spectroscopy in a Si/SiGe quantum dot
Date: Thursday, January 14th
Time: 10:00 am
Place: 5310 Chamberlin
Speaker: Madhu Thalakulam, UW-Madison
Abstract: Charge sensing with integrated point contacts is an essential component to the development of Si-based quantum dot spin qubits. Recently, we have shown that such charge sensing can be used to perform excited state spectroscopy in two complementary ways. In the first approach, pulsed gate voltages of increasing amplitude are applied to a gate. In the second approach, a non-zero dc source-drain bias is applied across the quantum dot. In neither case does measurable current flow through the dot. Instead, in both approaches excited states appear as sharp changes in time-averaged charge-sensing measurements performed with the integrated quantum point contact. The advantage of this approach is that it enables spectroscopy of quantum states when no transport is possible through the dot, which is a common situation for quantum dots in the one-electron limit. I will also present data demonstrating a Si/SiGe double quantum dot with exactly one-electron in each dot.
Host: Mark Eriksson
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