Relative stability of negative and positive trions in model symmetric quantum wires

Abstract

Binding energies of negative (X − ) and positive trions (X + ) in quantum wires are studied for strong quantum confinement of carriers which results in a numerical exactly solvable model. The relative electron and hole localization has a strong effect on the stability of trions. For equal hole and electron confinement, X + is more stable but a small imbalance of the particle localization towards a stronger hole localization e.g. due to its larger effective mass, leads to the interchange of X − and X + recombination lines in the photoluminescent spectrum as was recently observed experimentally. In case of larger X − stability, a magnetic field oriented parallel to the wire axis leads to a stronger increase of the X + binding energy resulting in a crossing of the X + and X − lines.

Two-electron lateral quantum-dot molecules in a magnetic field

“…12,13,18,[26][27][28][29][30][31][32][33] Magnetizations in QDs have been measured indirectly with transport measurements 34 and recently with a direct technique with improved sensitivity. 35 For both measurements, semiclassical approaches cannot explain the results.…”

Decay and persistence of spatial coherence during phonon-assisted relaxation in double quantum dots

“…We assume that the differences between the corresponding single-particle levels in the two dots are in the range of a few meV, hence much smaller than the energy of the electron-hole Coulomb attraction. The lowest exciton eigenstates are then formed by spatially direct states, that is, configurations in which the electron-hole pairs reside in the same dot 22,23 (presented in Fig. 1).…”

Dicke states in multiple quantum dots

“…Due to the strong Coulomb coupling and absence of the external electric fields we may restrict the discussion to 'spatially direct' excitonic states, i. e., states with electron-hole pairs residing in the same QD which in these conditions have much lower energy than the 'dissociated' states referring to excitons formed of carriers residing in two different dots. 56,57 These assumptions allow us to treat every QD as a two-level system which may be either empty or contain an exciton and thus describe the set of N QDs as an 2 N -level system, with |0 denoting the ground (or "vacuum") state in which all N dots are empty, single-exciton states |i , corresponding to one exciton localized in the ith QD, biexcitonic states |ij referring to electron-hole pairs residing in the ith and jth QDs, states |ijk with three QDs, ith, jth, and kth (1 i, j, k N ), occupied with an exciton etc.…”