Electric control of g-factors
The wavefunction of a particle confined within a quantum dot molecule is distributed over the entire molecular structure, which includes the barrier between the dots. Recently we discovered that the g-factor for a charge carrier confined in the molecular orbital changes with the application of an electric field. This effect occurs because the amplitude of the wavefunction within the barrier is tuned by the application of the electric field, which varies the relative energies of the ground states of each dot. Because the barrier has different material properties than the quantum dots, a change in the amplitude of the wavefunction in the barrier results in a change in the overall properties of the confined carrier. This technique could provide the basis of new electrical or optical techniques to control spins and spin interactions. We are studying the detailed physical mechanisms that create this effect, including the effect of spin-orbit interactions on hole states.
M.F. Doty, M. Scheibner, I.V. Ponomarev, E.A. Stinaff, A.S. Bracker, V.L. Korenev, T.L. Reinecke, D. Gammon. Electrically tunable g-factors in quantum dot molecular spin states. Phys. Rev. Lett. 97 197202 (2006)
A.S. Bracker, M. Scheibner, M.F. Doty, E.A. Stinaff, I.V. Ponomarev, J.C. Kim, L.J. Whitman, T.L. Reinecke, D. Gammon. Engineering electron and hole tunneling with asymmetric InAs quantum dot molecules. Appl. Phys. Lett. 89, 233110 (2006)
M.F. Doty, M. Scheibner, A.S. Bracker, I.V. Ponomarev, T.L. Reinecke, D. Gammon. Optical spectra of doubly charged quantum dot molecules in electric and magnetic fields Phys. Rev. B. 78 115316 (2008)
M.F. Doty, J.I. Climente, M. Korkusinski, M. Scheibner, A.S. Bracker, P. Hawrylak, D. Gammon. Antibonding molecular ground states in semiconductor artificial molecules. in review, cond-mat arXiv:0804.3097v1 (2008).