Dynamics of Discrete Breathers in a Pt3Al Crystal

Старостенков, М. Д.; Potekaev, A. I.; Zakharov, Pavel; Eremin, A. M.; Кулагина, В. В.

doi:10.1007/s11182-016-0654-6

Cited by 20 publications

(9 citation statements)

References 9 publications

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“…We considered the value α = 5, for which the equilibrium interatomic distance is a = 0.98813 at the potential cutoff radius of 5.5a. We note that the Morse potential was often used for the simulation of different properties of discrete breathers in crystals [23][24][25][26][27][28][29][40][41][42][43][44][45][46].…”

Section: Nonlinear Phenomenamentioning

confidence: 99%

“…In the last decade, discrete breathers in different crystals were studied in numerous works, including experimental investigations [4][5][6][7][8][9][10][11] and theoretical studies performed using ab initio approaches [12][13][14] and the molecular dynamics method . In particular, discrete breathers were studied in model crystals [15,16], in alkali-halide crystals [8,[17][18][19], in pure metals [7,[20][21][22], in ordered alloys [23][24][25][26][27][28][29], in covalent germanium and silicon crystals [30], and in carbon and hydrocarbon nanomaterials [12][13][14][31][32][33][34][35][36][37]. The further search for possible types of discrete breathers in different crystals is a topical and interesting problem, the solution of which will make it possible to answer the question about the role of the discrete breathers in the formation of the physical and mechanical properties of crystals.…”

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confidence: 99%

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Highly symmetric discrete breather in a two-dimensional Morse crystal

et al. 2016

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It has been shown recently that a moving discrete breathers localized in one close-packed atomic row can be excited in a two-dimensional monoatomic crystal with Morse interaction. In this work, a motionless discrete breathers having the threefold symmetry axis has been excited in the same crystal. The initial conditions for the excitation of such discrete breathers are set by the superposition of a bell-shaped function on a planar nonlinear phonon mode with the wave vector lying at the edge of the Brillouin zone. In addition, the displacement of the centers of atomic oscillations from the center of the discrete breathers owing to the asymmetry of the Morse potential is taken into account. The results obtained make it possible to approach the search for highly symmetric discrete breathers in three-dimensional crystals.

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Section: Nonlinear Phenomenamentioning

confidence: 99%

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confidence: 99%

Highly symmetric discrete breather in a two-dimensional Morse crystal

et al. 2016

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“…From this observation it follows that the heat capacity of the crystals having a gap in the phonon spectrum and supporting soft-type anharmonicity DBs (e.g., NaI [31,32,[38][39][40], ordered alloys [51][52][53][54], and graphane [37]) should increase due to the excitation of DBs. For the crystals without a gap in the phonon spectrum (e.g., pure metals [45][46][47][48][49][50] and covalent crystals [43,44]) only hard-type anharmonicity DBs can exist and their excitation will reduce heat capacity.…”

Section: Discussionmentioning

confidence: 92%

“…[39,40]. Using molecular dynamics, DBs have been found in monoatomic Morse crystals [41,42], covalent crystals Si, Ge and diamond [43,44], pure metals [45][46][47][48][49][50], ordered alloys [51][52][53][54], carbon and hydrocarbon nanomaterials [55][56][57][58][59][60][61][62][63][64][65][66][67], boron nitride [68], and proteins [69][70][71][72]. Essential limitation of any MD model is the choice of the interatomic potentials which largely determine the reliability of the obtained results [66].…”

Section: Introductionmentioning

confidence: 99%

Effect of discrete breathers on the specific heat of a nonlinear chain

Singh,

Morkina,

Korznikova

et al. 2019

Preprint

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Defect-free crystal lattices can accommodate spatially localized, high amplitude atomic vibrations called either discrete breathers (DBs) or intrinsic localized modes (ILMs). This has been explored by a number of molecular dynamics studies and, in few cases, by the first-principles calculations. A number of experimental measurements of crystal vibrational spectra was performed aiming to prove the existence of DBs in thermal equilibrium at elevated temperature. However, the interpretation of these experimental results is still debated. Direct high-resolution imaging of DBs in crystals is hardly possible due to their nanometer size and short lifetime. An alternative way to substantiate the existence of DBs is to evaluate their impact on the measurable macroscopic properties of crystals and validate such prediction. One of such properties is specific heat. In fact, the measurements of heat capacity was done for alpha-uranium by Manley and co-workers in conditions where the presence of DBs was expected. In the present study, employing a one-dimensional nonlinear lattice with an on-site potential, we analyze the effect of DBs on its specific heat. In the most transparent way, this can be done by monitoring the chain temperature in a non-equilibrium process, at the emergence of modulational instability, with total energy of the chain being conserved. For the onsite potential of hard-type (soft-type) anharmonicity, the instability of q = π mode (q = 0 mode) results in the appearance of long-living DBs that gradually dissipate their energy and eventually the system approaches thermal equilibrium with spatially uniform and temporally constant temperature. The variation of specific heat at constant volume is evaluated during this relaxation process. It is concluded that DBs affect specific heat of the nonlinear chain and for the case of hard-type (softtype) anharmonicity they reduce (increase) the specific heat.

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“…Because crystal has discrete structure and interaction between atoms is anharmonic, it has been expected that DBs exist in material as vibration modes in atomic scales. Excitation of DBs in material has been attracted since the early stage of study of DB [9][10][11][12][13][14][15][16]. Interaction between DBs and structures in crystal such as vacancy, dislocation and impurity has been also investigated [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Structure and stability of discrete breather in zigzag and armchair carbon nanotubes

Doi¹,

Nakatani²

2016

LoM

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Structure and stability of stationary discrete breathers (DBs) in armchair and zigzag carbon nanotubes (CNTs) are investigated numerically. Precise numerical solutions of DB in CNTs are calculated by a numerical method that couples the Newton-Raphson method and molecular dynamics method. Linear stability analysis is performed by constructing of monodromy matrix of the numerical solution of DB from the numerical results of MD simulation. In both structures of zigzag and armchair carbon nanotube, stationary DBs with higher angular frequency above zone boundary mode exist. Displacement of DB is on cylindrical plane of CNTs. Linear stability analysis shows that DBs in both armchair CNT and zigzag CNT are unstable. The maximum growth rate of the unstable perturbation mode can be calculated numerically. The maximum growth rate of armchair CNT is greater than that of zigzag CNT even when the curvature of the cylindrical plane of zigzag CNT is greater than armchair CNT. In both case of armchair and zigzag CNT, the unstable motion is excited in the direction out of the cylindrical plane of CNTs. Unstable dynamics is suppressed by introducing extensive strain in axial direction of CNT. In this case, motion of the unstable perturbation modes is confined on the cylindrical plane of CNTs.

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Dynamics of Discrete Breathers in a Pt3Al Crystal

Cited by 20 publications

References 9 publications

Highly symmetric discrete breather in a two-dimensional Morse crystal

Highly symmetric discrete breather in a two-dimensional Morse crystal

Effect of discrete breathers on the specific heat of a nonlinear chain

Structure and stability of discrete breather in zigzag and armchair carbon nanotubes

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