Direct measurement of the spin-orbit interaction in a two-electron InAs nanowire quantum dot

作者：Fasth C^*; Fuhrer A; Samuelson L; Golovach Vitaly N; Loss Daniel

来源：Physical Review Letters, 2007, 98(26): 266801.

DOI：10.1103/PhysRevLett.98.266801

We demonstrate control of the electron number down to the last electron in tunable few-electron quantum dots defined in catalytically grown InAs nanowires. Using low temperature transport spectroscopy in the Coulomb blockade regime, we propose a method to directly determine the magnitude of the spin-orbit interaction in a two-electron artificial atom with strong spin-orbit coupling. Because of a large effective g factor vertical bar g(*)vertical bar=8 +/- 1, the transition from a singlet S to a triplet T+ ground state with increasing magnetic field is dominated by the Zeeman energy rather than by orbital effects. We find that the spin-orbit coupling mixes the T+ and S states and thus induces an avoided crossing with magnitude Delta(SO)=0.25 +/- 0.05 meV. This allows us to calculate the spin-orbit length lambda(SO)approximate to 127 nm in such systems using a simple model.

• 出版日期2007-6-29