Boundary-condition effects in anharmonic lattice dynamics: Existence criteria for intrinsic localized modes from extended-mode properties

Bonart, D.; Rössler, Thomas; Page, J. B.

doi:10.1103/physrevb.55.8829

Cited by 12 publications

(20 citation statements)

References 25 publications

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“…This stability analysis assumes infinitesimal displacement and velocity perturbations having an exponential time dependence exp(λt), leading to a linear eigenvalue problem for the growth rates {λ}. In previous studies, 23,25 we have shown that a dynamical ExM instability with a purely real growth rate λ is intimately connected with the existence of ILMs associated with the ExM. The OZCM in our model lattice exhibits such an ILM-related instability.…”

Section: The Model: Interatomic Potentials and Characteristicsmentioning

confidence: 86%

“…We re-emphasize that these candidates for indirect optical creation of ILMs have two basic properties in common: (i) the k = 0 TO phonon in these materials is both first-order Raman and IR active, and (ii) the frequency of the k = 0 TO phonon is at the minimum of the TO branch along <111>, such that in conjunction with the fact that real potentials are dominated by soft anharmonicity, the criterion of Ref. 23 predicts the existence of gap ILMs associated with this k = 0 TO phonon.…”

Section: Relevance For Real Crystalsmentioning

confidence: 94%

“…In Ref. 23, we obtained an ILM existence criterion based on the interplay between fundamental harmonic and anharmonic dynamical properties of the ILM's associated ExM. For our case of interactions via realistic BMC potentials with their dominant soft anharmonicity, this criterion predicts the existence of ILMs associated with the OZCM in diatomic lattices for which the optical branch of the harmonic dispersion relation has a minimum at k = 0.…”

Section: The Model: Interatomic Potentials and Characteristicsmentioning

confidence: 97%

“…In a detailed study, 23 we noted that ILMs should be classified according to their "associated" extended lattice mode (ExM), into which they spatially broaden with decreasing amplitude. Since we are focusing on the optical creation of ILMs, we study a model that exhibits ILMs associated with the optically-active ExM.…”

Section: The Model: Interatomic Potentials and Characteristicsmentioning

confidence: 99%

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Optical creation of vibrational intrinsic localized modes in anharmonic lattices with realistic interatomic potentials

Rössler

Page

2000

Phys. Rev. B

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Using an efficient optimal control scheme to determine the exciting fields, we theoretically demonstrate the optical creation of vibrational intrinsic localized modes (ILMs) in anharmonic perfect lattices with realistic interatomic potentials. For systems with finite size, we show that ILMs can be excited directly by applying a sequence of femtosecond visible laser pulses at THz repetition rates. For periodic lattices, ILMs can be created indirectly via decay of an unstable extended lattice mode which is excited optically either by a sequence of pulses as described above or by a single picosecond far-infrared laser pulse with linearly chirped frequency. In light of recent advances in experimental laser pulse shaping capabilities, the approach is experimentally promising.

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Section: The Model: Interatomic Potentials and Characteristicsmentioning

confidence: 86%

Section: Relevance For Real Crystalsmentioning

confidence: 94%

Section: The Model: Interatomic Potentials and Characteristicsmentioning

confidence: 97%

Section: The Model: Interatomic Potentials and Characteristicsmentioning

confidence: 99%

See 2 more Smart Citations

Optical creation of vibrational intrinsic localized modes in anharmonic lattices with realistic interatomic potentials

Rössler

Page

2000

Phys. Rev. B

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“…As a result, the anharmonic version of the optical zone center ͑k 0͒ mode (OZCM) is both Raman and IR active. Within our interaction model, an ILM existence criterion based on an interplay between harmonic and anharmonic extended mode properties [10] is satisfied for the OZCM if the curvature of the harmonic optic mode dispersion curve is positive at k 0. The measured transverse phonon branches of ZnS along the (111) direction exhibit this behavior, so we choose potential parameters which approximately match those curves.…”

mentioning

confidence: 99%

Creation of Intrinsic Localized Modes via Optical Control of Anharmonic Lattices

Rössler

Page

1997

Phys. Rev. Lett.

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The optical creation of intrinsic localized modes in perfect anharmonic lattices with realistic interatomic potentials is demonstrated theoretically, using an efficient optimal control scheme to determine experimentally feasible exciting fields. [S0031-9007(97) PACS numbers: 63.20. Ry, 63.20.Pw, 78.20.Bh Intrinsic localized modes (ILMs) are novel vibrational excitations in periodic lattices, characterized by displacement patterns which can be highly localized [1]. In contrast to localized impurity modes in harmonic defect crystals, ILMs in perfect lattices result from anharmonicity in the interparticle potentials. Recent studies have obtained ILMs for increasingly realistic models [2,3]. However, beyond a theoretical demonstration that driven ILMs can exist as a steady-state response to an applied spatially homogeneous sinusoidal driving force [4], the key experimental question of how ILMs might be created externally has not been addressed, and ILMs have not yet been verified in the laboratory. Here we describe an avenue for the experimental creation of ILMs. It is shown how ILMs can be produced in a one-dimensional model lattice with realistic potentials by means of laser pulses whose time dependence is designed by an efficient optimal control scheme. Aspects of the experimental feasibility of the approach are discussed.Owing to their high power densities, lasers are appropriate sources for exciting large-amplitude well-localized ILMs. Recent developments in experimental laser pulse shaping techniques [5,6] provide considerable flexibility in the time dependence of the applied force. Indeed, the use of tailored fields for vibrational excitation has attracted much recent interest, mainly in the context of optical control of dissociation and reactions in molecular chemistry [7], but also for the selective excitation of optical phonons in time-domain spectroscopy [8]. We will focus on two methods for transient optical creation of ILMs: impulsive stimulated Raman scattering (ISRS) excitation [9] by a sequence of femtosecond pulses at THz repetition rates from a laser operating at near visible frequencies, and infrared (IR) excitation by a picosecond far-IR laser pulse. For both mechanisms, the system's dynamical response can be described classically, provided the underlying laser frequency for the ISRS case is well off resonance with vibrational and electronic transitions.For longitudinal motion in a driven 1D system, the Hamiltonian is H X n h p 2 n 2m n 1 X l V n,n2l ͑r n 2 r n2l ͒ 2 F ext n ͑t͒r n i ,where particle n has mass m n , position r n , and momentum p n , and interacts with particle n 2 l via a potential V n,n2l . The external force is F ext n ͑t͒ 1 2 P n E 2 ͑t͒ and F ext n ͑t͒ q n E ͑t͒ for ISRS and IR excitation, respectively. Here E ͑t͒ is the longitudinally polarized electric field, P n ϵ ͑≠P ͞≠r n ͒ 0 is the electronic polarizability derivative evaluated at the equilibrium configuration, and q n is the effective charge.Our model is a 1D diatomic lattice with masses m and M ͑.m͒ and nearest-nei...

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Temporal Fourier spectra of stationary and slowly moving breathers in Fermi–Pasta–Ulam anharmonic lattice

Kosevich

Corso

2002

Physica D: Nonlinear Phenomena

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Boundary-condition effects in anharmonic lattice dynamics: Existence criteria for intrinsic localized modes from extended-mode properties

Cited by 12 publications

References 25 publications

Optical creation of vibrational intrinsic localized modes in anharmonic lattices with realistic interatomic potentials

Optical creation of vibrational intrinsic localized modes in anharmonic lattices with realistic interatomic potentials

Creation of Intrinsic Localized Modes via Optical Control of Anharmonic Lattices

Temporal Fourier spectra of stationary and slowly moving breathers in Fermi–Pasta–Ulam anharmonic lattice

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