Measurement of Tunnel Coupling in a Si Double Quantum dot Based on Charge Sensing

Abstract

Tunnel coupling is a key parameter in coupled semiconductor quantum dots, and is a crucial ingredient in various device applications, such as exchange gates and spin shuttling in quantum information processing. A widely used charge-sensing technique to extract the tunnel coupling of a double quantum dot accounts for only the ground orbital state in each dot, but the authors show that in a Si double dot, valley-orbit coupling must be included in the analysis. With their more complete model, one can not only extract the $i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}v\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}y$ (ground-state) tunnel coupling more accurately, but also obtain information on $i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}v\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}y$ (ground-to-excited-state) tunnel coupling.

Topics & Concepts