Vibronic quantum beats in PbS microcrystallites

Machol, J. L.; Wise, Frank W.; Patel, Ramesh C.; Tanner, D. B.

doi:10.1103/physrevb.48.2819

Cited by 308 publications

(207 citation statements)

References 23 publications

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“…The signal decayed as exp(−4τ /T 2 ) with T 2 ∼ 440f s. From the measured dephasing time T 2 a homogeneous linewidth of ∼ 3 meV can be obtained, in agreement with previous measurements 13 . Low energy acoustic phonons can efficiently scatter excitons in the highly degenerate spin states within the manifold in PbS quantum dots and are generally thought to be the mechanism behind the rapid dephasing in colloidal quantum dots [13][14][15][16][17][18] .…”

Section: Resultsmentioning

confidence: 99%

Quantum beats due to excitonic ground-state splitting in colloidal quantum dots

et al. 2012

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The dephasing of PbS quantum dots has been carefully measured using three pulse four-wave mixing and two-dimensional nonlinear optical spectroscopy. The temperature dependence of the homogeneous linewidth obtained from the two-dimensional spectra indicates significant scattering by acoustic phonons, whereas the excitation density dependence shows negligible excitation induced broadening in agreement with previous results. The rapid dephasing is attributed to elastic scattering by acoustic phonons. However, two dephasing components emerge, the short component that dominates the decay and a weaker longer decay, likely due to 'zero-phonon' dephasing. Quantum beats originating from two separate states can be observed, possibly revealing a ∼23.6 meV splitting of the excitonic ground state. Finally, the emergence of biexcitonic effects enhanced by the high quantum confinement is discussed.

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Section: Resultsmentioning

confidence: 99%

Quantum beats due to excitonic ground-state splitting in colloidal quantum dots

et al. 2012

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“…Coherent optical and acoustic modes have been observed recently in semiconductor quantum dots 128,129,130,131,132]. Resonant excitation of quantum dots in conjunction with strong electron-phonon coupling leads to a modulation of a four wave mixing signal with the frequency of the LO phonon in CdSe quantum dots 128,129] and of the LO and TO mode in InP quantum dots 131].…”

Section: Recent Developmentsmentioning

confidence: 99%

Coherent phonons in condensed media

Dekorsy¹,

Cho²,

Kurz³

2000

Topics in Applied Physics

139

127

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Abstract. The impulsive excitation and phase-sensitive detection of coherent phonons and phonon-polaritons provide a detailed insight i n to the dynamical properties of matter. The experiments are based on optical pump-probe techniques with femtosecond time resolution. These techniques enable the detection of amplitude and phase of the coherent lattice motion simultaneously. F requencies in the THz range and dephasing times in the picosecond range can be obtained with high accuracy. Especially in semiconductors and semiconductor heterostructures, where a coherent phonon mode and free carriers are excited simultaneously, important information about carrier-phonon interaction far away from equilibrium is obtained. This paper presents an overview of recent a c hievements in this vivid eld of condensed matter physics.

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“…Lead sulphide (PbS) is one such important narrow band-gap semiconductor from IV-VI groups with a band gap of 0.4 eV at 300 K and has a relatively large excitation Bohr radius (EBR) of 18 nm [1]. Due to its larger EBR, the quantum confinement effect could be observed to a much higher particle size and band-gap energy of PbS can be tuned from 0.41 to 2.3 eV by changing the mean nanocluster size [2]. These properties make PbS a very suitable candidate for infrared detection application [3], photography [4], Pb 2þ ion-selective sensors [5], display devices [6] and solar absorption [7].…”

Section: Introductionmentioning

confidence: 99%