Origin of two-hole triplet splitting in circular quantum dots

Using the k·p theory and configuration interaction method, we analyze the effect of heavy hole–light hole (HH–LH) mixing in CdTe quantum dots (QDs) with a single manganese (Mn) ion. We find that the hole‐Mn exchange switches the coupling between two excitons whose Luttinger spinors have both HH and LH components. If the magnetic dopant is off‐centered and the QD is subjected to a single π pulse the system periodically bounces between bright and dark mostly HH excitons with opposite HH spins. A pump‐and‐probe setup allows to estimate the efficiency of this HH spin unpinning from the biexciton response. The biexciton absorption spectrum is also discussed.

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“…We present results for a QD of radius

R = 5

nm and height

W = 8

nm. The aspect ratio

W / 2 R

controls the HH–LH mixing within a Luttinger spinor . Typically, one has a single dominant component

false| φ_{m_{z} italicnl}, J_{z} 〉

and some minor components.…”

Section: Resultsmentioning

confidence: 99%

“…Indeed, Siebert et al argued that the HH–LH coupling induces the zero‐field splitting within the p ‐shell hole states. Later on, Climente discussed the role of the HH–LH coupling on the two‐hole triplet splitting and on the spin purity of charged trions in InAs/GaAs QDs.…”

Section: Introductionmentioning

confidence: 99%

Unpinning of heavy hole spin in magnetic quantum dots

Dinu

Moldoveanu

Dragomir

et al. 2016

Physica Status Solidi (b)

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“…It is well known that a light-hole ground state in optically active QDs can be experimentally achieved either by tuning the aspect ratio (i.e., height/radius ratio) [26,27] or by applying tensile strain on the structure [28]. Here we take the first route and investigate QDs whose dominant light-hole character of ground-state excitons is controlled by the aspect ratio.…”

Section: Introductionmentioning

confidence: 99%

Light-hole exciton mixing and dynamics in Mn-doped quantum dots

et al. 2016

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We investigate theoretically the spectral and dynamical effects of the short-range exchange interaction between a single manganese (Mn) atom hosted by cylindrical CdTe quantum dots and its light-hole excitons or biexcitons. Our approach is based on the Kohn-Luttinger k · p theory and configuration interaction method, the dynamics of the system in the presence of intraband relaxation being derived from the von Neumann-Lindblad equation. The complex structure of the light-hole exciton absorption spectrum reveals the exchange-induced exciton mixing and depends strongly on the Mn position. In particular, if the Mn atom is closer to the edges of the cylinder, the bright and dark light-hole excitons are mixed by the hole-Mn exchange alone. Consequently, their populations exhibit exchange-induced Rabi oscillations which can be viewed as optical signatures of light-hole spin reversal. Similar results are obtained for mixed biexcitons, in this case the exchange-induced Rabi oscillations being damped by the intraband hole relaxation processes. The effect of light-hole heavy-hole mixing is also discussed.

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“…The valencehole states are obtained from the multiband LuttingerKohn k · p theory 23 and therefore we can also deal with QDs in which light-holes (LH) and heavy-holes (HH) are mixed 24 . We obtain the exciton and biexciton states in the presence of both interband and intraband Coulomb interaction.…”

Section: Introductionmentioning

confidence: 99%

“…The aim of this work is to address theoretically the dynamics of sp biexcitons in disk-shaped quantum dots in the presence of intraband relaxation. The valencehole states are obtained from the multiband Luttinger-Kohn k • p theory 23 and therefore we can also deal with QDs in which light-holes (LH) and heavy-holes (HH) are mixed 24 . We obtain the exciton and biexciton states in the presence of both interband and intraband Coulomb interaction.…”

Section: Introductionmentioning

confidence: 99%

Dynamics and relaxation ofspbiexcitons in disk-shaped quantum dots

2014

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We study the effects of intraband relaxation processes on optical manipulation protocols for sp biexcitons hosted by CdTe disk-shaped quantum dots. The many-body states are calculated within the configuration interaction method starting from single-particle states given by the k · p theory. The time-dependent occupations of relevant many-body states are extracted from the von NeumannLindblad equation for the density operator. We mainly investigate the generation of sp biexcitons with two pulses of different polarizations σ+ and σ−. The fast hole relaxation processes prevent a high-fidelity controlled operation on sp biexcitons and lead to the occupation of some transient states which can be optically probed. More importantly, the many-body structure of the transient states consists of two holes on the s shell and antiparallel sp triplet states for electrons. Our simulations show that these triplet states are more stable against decoherence as they can only be damaged through slow electron relaxation. The configuration mixing due to correlation effects is also discussed.

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Origin of two-hole triplet splitting in circular quantum dots

Cited by 5 publications

References 25 publications

Unpinning of heavy hole spin in magnetic quantum dots

Unpinning of heavy hole spin in magnetic quantum dots

Light-hole exciton mixing and dynamics in Mn-doped quantum dots

Dynamics and relaxation ofspbiexcitons in disk-shaped quantum dots

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