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Si-Based Single Spin Coherence and Manipulation

Summary

We are characterizing Si-based single-electron quantum dots at low temperatures (down to 10 mK) to explore the possibility of quantum coherent manipulation in Si-based technology.

Description

bias-triangle

"Bias triangles" showing large electrical current in triangle-shaped regions of gate voltage space. An extension of the standard double quantum dot theory (dashed lines) demonstrates good agreement between theory and experiment for a comprehensive test with four different biasing conditions (no free parameters).

Devices based on moving and controlling single electrons offer the tantalizing possibility of achieving quantum information processing by virtue of their spin or charge coherent properties. We are pursuing CMOS-compatible Si-based SET double quantum dots to explore the possibility of quantum coherent manipulation. The spin degree of freedom of these quantum dots can be controlled with a combination of magnetic fields and high-frequency electrical pulses.

Efforts include:

  • Understanding the basic physics interaction of magnetic fields with the electron states in double quantum dots. This includes i) investigating the theoretical and experimental consequences of high magnetic fields on transport; ii) investigating the theoretical and experimental effects of including the Si valley degree of freedom.
  • Understanding the experimental and theoretical sources of decoherence, including i) defect-based noise and ii) the effects of randomvalley phase due to interface roughness.
  • Developing multiple measurement systems which combine i) high magnetic fields up to 8 T with ii) low electron temperature down to 10 mK and iii) high-frequency continuous wave and pulsed electrical signals.

*This work is done in close collaboration with the team of Michael Stewart, Jr., and the devices produced for the quantum coherent experiments are very similar to those used for current standard experiments.

Created July 14, 2015, Updated October 1, 2018