BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:UW-Madison-Physics-Events BEGIN:VEVENT SEQUENCE:0 UID:UW-Physics-Event-1614 DTSTART:20091119T160000Z DURATION:PT1H0M0S DTSTAMP:20260416T185927Z LAST-MODIFIED:20091116T195424Z LOCATION:5310 Chamberlin SUMMARY:Silicon metal insulator semiconductor nanostructures for solid -state quantum computing\, R. G. Herb Condensed Matter Seminar\, Malco lm Carroll\, Sandia National Laboratory DESCRIPTION:Development of silicon\, enhancement mode\, metal insulato r semiconductor (MIS) nanostructures for solid-state quantum computing will be described. A primary motivation of this research is the rece nt unprecedented manipulation of single electron spins in GaAs quantum dots\, which has been used to demonstrate a quantum bit [1]. Quantum bits (qubits) are a fundamental element for quantum computing that al so represent an extraordinary probe of single electron spin physics in semiconductors. A critical challenge for quantum computing is develo pment of qubits that maintain long spin decoherence times\, which will allow the necessary number of spin operations to be done before the i nformation is lost due to spin decoherence. Development of silicon na nostructures for qubits are being pursued around the world because ele ctron spins in silicon are predicted to have long decoherence times.
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\nThis talk will focus on silicon quantum dot structures t hat emulate the GaAs lateral quantum dot qubit [1] but use an enhancem ent mode field effect transistor (FET) structure. One critical concer n for silicon quantum dots that use oxides as insulators in the FET st ructure is that defects in the metal oxide semiconductor (MOS) stack c an produce both detrimental electrostatic and paramagnetic effects on the qubit. Understanding the implications of defects in the Si MOS sy stem is also relevant for other qubit architectures that have nearby d ielectric passivated surfaces. Stable\, lithographically defined\, si ngle-period Coulomb-blockade and single-electron charge sensing in a q uantum dot nanostructure using a MOS stack will be presented. A combi nation of characterization of defects\, modeling and consideration of modified approaches that incorporate SiGe or donors provides guidance about the enhancement mode MOS approach for future qubits and quantum circuit micro-architecture.
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\nWe wish to acknowledge the re search funding support provided by the laboratory directed research an d development (LDRD) program at Sandia National Laboratories and the L aboratory of Physical Sciences. Sandia National Labs is a multi-progr am laboratory operated by Sandia Corporation\, a Lockheed Martin Compa ny\, for the United States Department of Energy's National Nuclear Sec urity Administration under contract DE-AC04-94AL85000.
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\n [1] J. Petta et al.\, Science 309\, 2180 (2005) URL:https://www.physics.wisc.edu/events/?id=1614 END:VEVENT END:VCALENDAR