Atomistic study of two-dimensional discrete breathers in hcp titanium

A general approach is applied to study a new type of intrinsic spatially localized vibrational modes in a defect free nonlinear crystal lattice, i.e., discrete breathers (DBs). For that, dynamics of eight delocalized nonlinear vibrational modes (DNVMs) of two-dimensional triangular lattice is invest...

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Bibliographic Details
Published in:The European physical journal. B, Condensed matter physics Condensed matter physics, 2022-07, Vol.95 (7), Article 104
Main Authors: Bachurina, O. V., Murzaev, R. T., Kudreyko, A. A., Dmitriev, S. V., Bachurin, D. V.
Format: Article
Language:English
Subjects:
Analysis
Breathers
Complex Systems
Condensed Matter Physics
Crystal defects
Crystal lattices
Dimensional stability
Fluid- and Aerodynamics
Lattice vibration
Material properties
Molecular dynamics
Nonlinearity
Oscillations
Physical properties
Physics
Physics and Astronomy
Regular Article - Computational Methods
Single crystals
Solid State Physics
Titanium
Vibration mode
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Summary:A general approach is applied to study a new type of intrinsic spatially localized vibrational modes in a defect free nonlinear crystal lattice, i.e., discrete breathers (DBs). For that, dynamics of eight delocalized nonlinear vibrational modes (DNVMs) of two-dimensional triangular lattice is investigated in three-dimensional single crystal of hcp Ti. Molecular dynamics simulations are performed using two interatomic potentials (Ti_EAM and Ti_MEAM). The eight DNVMs modeled with Ti_EAM potential are found to be unstable and dissipate their vibrational energy very rapidly. The usage of Ti_MEAM interatomic potential allows to excite stable two-dimensional (planar) DBs. These localized vibrational modes can be called DBs, since the frequency of atomic oscillations is above the upper edge of the phonon spectrum of Ti, and the atomic oscillations are localized in one spatial direction and delocalized in the other two directions. The lifetimes of the two-dimensional DBs are in the range of 5–14 ps, while the maximal lifetime of DBs excited on the basis of DNVM 7 is circa 28 ps. These DBs can accumulate vibrational energy, which is in the range of 0.1–0.5 eV per atom. The stable two-dimensional DBs are characterized by a hard type of nonlinearity. A comparison with analogous two-dimensional DBs in fcc metals are undertaken. The obtained results make a significant contribution to the study of DBs in metals and will be important for understanding the influence of intrinsic localized vibrational modes on the physical properties of materials. Graphical abstract
ISSN:1434-6028
1434-6036
DOI:10.1140/epjb/s10051-022-00367-0