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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-6220
DTSTART:20210308T200000Z
DURATION:PT1H0M0S
DTSTAMP:20260415T010924Z
LAST-MODIFIED:20210303T135855Z
LOCATION:https://uwmadison.zoom.us/j/94566927415?pwd=MUtXazdPZEhDSVduZ
 HVmemZIRktKdz09
SUMMARY:Electron-electron interactions in Si/SiGe Quantum Dots\, Gradu
 ate Program Event\, Ekmel Ercan\, Physics PhD Graduate Student
DESCRIPTION:In this talk I present our work on the effects of confinem
 ent strength on two-electron states in an electrostatically-defined qu
 antum dot in a Si/SiGe quantum well at zero magnetic field\, focusing 
 on geometries appropriate for qubits. I will discuss that the experime
 ntal signatures of strong electron-electron (e-e) interactions in thes
 e devices can be subtle. While the suppression of the singlet-triplet 
 splitting in two-electron quantum dots formed in direct band gap mater
 ials is a clear indication of e-e interactions\, in silicon devices th
 is effect can be masked by the additional valley degree of freedom of 
 the conduction band electrons\, when the quantum well interface is fla
 t. I will further argue that interfacial-disorder-induced valley-orbit
  coupling\, on the other hand\, can induce this suppression. Next\, I 
 will discuss implications of this physics on charge noise sensitivity 
 and demonstrate calculations indicating that dramatic changes in depha
 sing times can be observed by slightly changing the confinement streng
 th. Finally\, I will discuss the role of e-e interactions in two recen
 t experiments demonstrating (1) the use of valley-orbit states to prob
 e Si/SiGe interface\, and (2) a spectroscopically-dense set of low-lyi
 ng energy levels.
URL:https://www.physics.wisc.edu/events/?id=6220
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