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Tunable singlet-triplet splitting in a few-electron Si/SiGe quantum dot

Research output: Contribution to journalJournal article


  • Zhan Shi
  • C. B. Simmons
  • J. R. Prance
  • John King Gamble
  • Mark Friesen
  • D. E. Savage
  • M. G. Lagally
  • S. N. Coppersmith
  • M. A. Eriksson
Article number233108
<mark>Journal publication date</mark>5/12/2011
<mark>Journal</mark>Applied Physics Letters
Number of pages3
<mark>Original language</mark>English


We measure the excited-state spectrum of a Si/SiGe quantum dot as a function of in-plane magnetic field and identify the spin of the lowest three eigenstates in an effective two-electron regime. We extract the singlet-triplet splitting, an essential parameter for spin qubits, from the data. We find it to be tunable by lateral displacement of the dot, which is realized by changing two gate voltages on opposite sides of the device. We present calculations showing the data are consistent with a spectrum in which the first excited state of the dot is a valley-orbit state. (C) 2011 American Institute of Physics. [doi:10.1063/1.3666232]