A few-electron quadruple quantum dot in a closed loop
  We report the realization of a quadruple quantum dot device in a square-like configuration where a single electron can be transferred on a closed path free of other electrons. By studying the stability diagrams of this system, we demonstrate that we are able to reach the few-electron regime and to control the electronic population of each quantum dot with gate voltages. This allows us to control the transfer of a single electron on a closed path inside the quadruple dot system. This work opens the route towards electron spin manipulation using spin-orbit interaction by moving an electron on complex paths free of electrons 
Romain Thalineau (NEEL), Sylain Hermelin (NEEL), Andreas D. Wieck,   Christopher B\"auerle (NEEL), Laurent Saminadayar (NEEL...
cond-mat.mes-hall