TY - JOUR
T1 - Radiative cascade from quantum dot metastable spin-blockaded biexciton
AU - Kodriano, Y.
AU - Poem, E.
AU - Lindner, N. H.
AU - Tradonsky, C.
AU - Gerardot, B. D.
AU - Petroff, P. M.
AU - Avron, J. E.
AU - Gershoni, D.
PY - 2010/10/29
Y1 - 2010/10/29
N2 - We detect a radiative cascade which initiates from a metastable biexciton state in a neutral semiconductor quantum dot. In this biexciton, the heavy holes form a spin-triplet configuration, Pauli blockaded from relaxation to the spin-singlet ground state. The triplet biexciton has two photon-phonon-photon decay paths. Unlike in the singlet-ground-state biexciton radiative cascade, in which the two photons are colinearly polarized, in the triplet-biexciton cascade they are cross-linearly polarized. We measured the two-photon polarization density matrix and show that the phonon emitted when the intermediate exciton relaxes from excited to ground state, preserves the exciton's spin. The phonon, thus, does not carry with it any which-path information other than its energy. Nevertheless, entanglement distillation by spectral filtering was found to be rather ineffective for this cascade. This deficiency results from the opposite sign of the anisotropic electron-hole exchange interaction in the excited exciton relative to that in the ground exciton. © 2010 The American Physical Society.
AB - We detect a radiative cascade which initiates from a metastable biexciton state in a neutral semiconductor quantum dot. In this biexciton, the heavy holes form a spin-triplet configuration, Pauli blockaded from relaxation to the spin-singlet ground state. The triplet biexciton has two photon-phonon-photon decay paths. Unlike in the singlet-ground-state biexciton radiative cascade, in which the two photons are colinearly polarized, in the triplet-biexciton cascade they are cross-linearly polarized. We measured the two-photon polarization density matrix and show that the phonon emitted when the intermediate exciton relaxes from excited to ground state, preserves the exciton's spin. The phonon, thus, does not carry with it any which-path information other than its energy. Nevertheless, entanglement distillation by spectral filtering was found to be rather ineffective for this cascade. This deficiency results from the opposite sign of the anisotropic electron-hole exchange interaction in the excited exciton relative to that in the ground exciton. © 2010 The American Physical Society.
UR - http://www.scopus.com/inward/record.url?scp=78149250618&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.82.155329
DO - 10.1103/PhysRevB.82.155329
M3 - Article
SN - 1098-0121
VL - 82
SP - -
JO - Physical Review B: Condensed Matter and Materials Physics
JF - Physical Review B: Condensed Matter and Materials Physics
IS - 15
M1 - 155329
ER -