Longitudinal optical phonons in the excited state of CuBr quantum dots

Zhao, Jialong; Kanno, Atsushi; Ikezawa, Michio; Masumoto, Yasuaki

doi:10.1103/physrevb.68.113305

Cited by 5 publications

(6 citation statements)

References 21 publications

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“…3(a) with dispersionless longitudinal optical (LO) phonons6162636465 confined to the ZnSe nanocrystal. Removal of the accidental degeneracy at point A is seen to result in energy splitting of two out of the six initially degenerate states.…”

Section: Resultsmentioning

confidence: 99%

Level Anticrossing of Impurity States in Semiconductor Nanocrystals

Baimuratov

Rukhlenko

Turkov

et al. 2014

Sci Rep

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The size dependence of the quantized energies of elementary excitations is an essential feature of quantum nanostructures, underlying most of their applications in science and technology. Here we report on a fundamental property of impurity states in semiconductor nanocrystals that appears to have been overlooked—the anticrossing of energy levels exhibiting different size dependencies. We show that this property is inherent to the energy spectra of charge carriers whose spatial motion is simultaneously affected by the Coulomb potential of the impurity ion and the confining potential of the nanocrystal. The coupling of impurity states, which leads to the anticrossing, can be induced by interactions with elementary excitations residing inside the nanocrystal or an external electromagnetic field. We formulate physical conditions that allow a straightforward interpretation of level anticrossings in the nanocrystal energy spectrum and an accurate estimation of the states' coupling strength.

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Section: Resultsmentioning

confidence: 99%

Level Anticrossing of Impurity States in Semiconductor Nanocrystals

Baimuratov

Rukhlenko

Turkov

et al. 2014

Sci Rep

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“…Comparison of luminescence and scattering contributions to the total signal of secondary emission given in Eqs. (20), (21), and (23) reveals several important differences between their spectra. First, if the frequency of excitation is out of resonance with either of the electronic transitions, then the position of the scattering maximum coincides with ω L , whereas the luminescence intensity peaks at frequencies…”

Section: Spectral Filtration Of Secondary Emissionmentioning

confidence: 99%

“…The obtained density matrix elements are then introduced into the expression similar to Eq. (20) to find that the differential cross section of the secondary emission is given by…”

Section: Secondary Emission In the Case Of Resonance With Degenerate mentioning

confidence: 99%

“…Although quantum dots are generally affected by a multitude of phonon-related elementary excitations-residing both inside them and in various distant parts of the host heterostructures [14][15][16][17]-the renormalizations of the quantum dot's energy spectra, that have been experimentally observed so far, predominantly resulted from polar interaction with longitudinaloptical (LO) phonons [13,[18][19][20][21][22][23]. Despite a relatively high strength of polar interaction compared to other types of electron-phonon coupling [1,2], the energy splitting of polaron-like states induced by the vibrational resonance is typically of the order of few millielectronvolts.…”

Section: Introductionmentioning

confidence: 99%

“…Quantum dots of different sizes emit light of different wavelengths leading to the inhomogeneous broadening of spectroscopic transitions. This obstacle can be avoided by applying size-selective optical methods, such as persistent spectral hole burning in an inhomogeneously broadened light absorption profile [20,24], one-and two-photon excited pho-toluminescence [13,22], or a single-quantum-dot spectroscopy [25,26]. Using these methods for studying the effect of vibrational resonance requires an adequate theoretical treatment of the underlying optical phenomena, taking into account specific features characteristic to the quantum dot's polaron-like spectrum.…”

Section: Introductionmentioning

confidence: 99%

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Theory of quasi-elastic secondary emission from a quantum dot in the regime of vibrational resonance

et al. 2011

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We develop a low-temperature theory of quasi-elastic secondary emission from a semiconductor quantum dot, the electronic subsystem of which is resonant with the confined longitudinal-optical (LO) phonon modes. Our theory employs a generalized model for renormalization of the quantum dot's energy spectrum, which is induced by the polar electron-phonon interaction. The model takes into account the degeneration of electronic states and allows for several LO-phonon modes to be involved in the vibrational resonance. We give solutions to three fundamental problems of energy-spectrum renormalization--arising if one, two, or three LO-phonon modes resonantly couple a pair of electronic states--and discuss the most general problem of this kind that admits an analytical solution. With these results, we solve the generalized master equation for the reduced density matrix, in order to derive an expression for the differential cross section of secondary emission from a single quantum dot. The obtained expression is then analyzed to establish the basics of optical spectroscopy for measuring fundamental parameters of the quantum dot's polaron-like states.

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