Physics and Astronomy PhD Thesis Defense - Zhen Yang, Dartmouth College

Title: "Superconducting Single Electron Transistor for Charge Sensoring in Si/SiGe-Based Quantum Dots."

September 15, 2015
2 pm - 4 pm
Location
Wilder 202
Sponsored by
Physics & Astronomy Department
Audience
Public
More information
Tressena Manning
603-646-2854

Abstract: Si-based quantum devices, including Si/SiGe quantum dots (QD), are promising candidates for spin-based quantum bits (quits), which are a potential platform for quantum information processing. Meanwhile, qubit readout remains a challenging task related to semiconductor-based quantum computation. The thesis describes two readout devices for Si/SiGe QDs and the techniques for developing them from a traditional single electron transistor (SET). By embedding an SET in a tank circuit and operating it in the radio-frequency (RF) regime, a superconducting RF-SET has quick response as well as ultra high charge sensitivity and can be an excellent charge sensor for the QDs. We demonstrate such RF-SETs for QDs in a Si/SiGe heterostructure. Characterization of the SET in magnetic fields is studied for future exploration of advanced techniques such as spin detection and spin state manipulation. By replacing the tank circuit with a high-quality-factor microwave cavity, the embedded SET will be operated in the supercurrent regime as a single Cooper pair transistor (CPT) to further increase the charge sensitivity and reduce any dissipation. The operating principle and implementation of the cavity-embedded CPT (cCPT) will be introduced.

 
 
Location
Wilder 202
Sponsored by
Physics & Astronomy Department
Audience
Public
More information
Tressena Manning
603-646-2854