Title: Valley Splitting in Silicon Quantum Dots

Speaker: Dr. Mark Friesen, University of Wisconsin-Madison

Date/Time: Wednesday, March 19, 2008, 2:00pm

Location: CSRI Building, Room 90 (Sandia NM)

Brief Abstract: Electron spins in silicon quantum dots can form robust qubits when their valley levels are sufficiently separated.  However, nature provides an interference mechanism to suppress the valley splitting, in the presence of ubiquitous atomic steps at the quantum well interface.  Fortunately, a number of control knobs are available for mitigating the effect.  In this talk, I present an overview of valley splitting and describe recent experiments showing that valley splitting can be restored to its theoretical maximum, in spite of interfacial steps.  We conclude that valley interference should in no way compromise two-electron gate operations in a quantum computer, which rely on the exchange interaction.

CSRI POC: Malcolm Carroll, (505) 284-3499, Mike Lilly, (505) 284-7778, Rick Muller, (505) 284-3669