Single electron Transport in diluted magnetic semiconductor quantum dots Department of Applied Physics, U. Alicante SPAIN Material Science Institute of Madrid, CSIC SPAIN J. Fernández-Rossier, R. Aguado Spin dependent Capacitance Z19-1 Gate Tuning Anisotropy CdTe+1 Mn
GaMnAs Single electron transistor cond-mat/ Coulomb blockade anisotropic magnetoresistance: Single electronics meets spintronics Authors:J. Wunderlich et al.
Mn (2+) S=5/2 2S+1=6 PL Intensity Y. Léger et al., PRL 95, (05) L. Besombes et al. PRL 93, (04) Single Exciton Spectroscopy 1 Mn per dot
S T =S e +M Heisenberg Ising MzMz
Single exciton spectroscopy (1 Mn dot) EXPERIMENTS: Y. Léger et al. PRL 95, (05) THEORY: J. Fernández-Rossier, PRB73, (06) WE UNDERSTAND e+h+Mn
Theory I: The dot STATES NUMERICAL DIAGONALIZATION STATES WITH a FIXED NUMBER of CARRIERS (Controlled By Gate Voltage)
GATE CONTROL of Magnetic Anisotropy Heisenberg STST Q=-1Q=0Q=+1Q=+3 Free HH LH Ising Z XX MzMz
MASTER EQUATION Scattering Rates Theory: Single electron transport Density matrix ( V g, V b )
CHARGING the dot E Q=0 Q=1 Q=2 VGVG VGVG Q Q=0 Q=1 Q=2 G
CHARGING the dot S=3 S=2 Spin dependent CHARGING ENERGY 3 PEAKS instead of 1 !!
VGVG E
VGVG E
VGVG E
VGVG E Q=0
VGVG E Q=1/3
VGVG E Q=2/3
VGVG E Q=3/3
Inelastic single spin spectroscopy
CONCLUSIONS Electric Tuning of magnetic anisotropy Ising Z XX MzMz SPIN conditional charging energy Q=+1 Q=+3