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arXiv 1809.08901nlin.PS
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单原子链中的新型离散呼吸子

Discrete breathers of new type in monoatomic chains

G. M. Chechin, V. S. Lapina

摘要:

在具有Lennard-Jones相互作用的应变单原子链中,我们揭示了一种稳定的静态非均匀结构,这种结构是由于某种相变而出现的。单个粒子在这种结构中的位置形成了一个精确的算术级数,其差值取决于应变的值。对于N粒子链,这种结构的特征是由一个长和N-1个短的原子间距离(键)。在静态结构附近,我们发现了与传统呼吸子有本质区别的新型离散呼吸子,它们的形式为Sievers-Takeno和Page模。众所周知,这些模式具有一些交错的结构,并表现出指数衰减的粒子振幅从核心到他们的尾巴。与这些性质相反,我们的呼吸器的特征是平滑衰减,粒子的振幅近似形成一个递减的算术级数。在静态结构中,这些呼吸子的核心位于两个长键粒子上。我们的呼吸子表现出软型非线性(频率随振幅的增加而降低),当振幅达到等间距链的20%-30%时,它们是稳定的动力学对象。对于无限小的振幅,这些呼吸器倾向于上述静态非均匀结构。我们研究了它们的性质对振幅、应变和链中粒子数的依赖性。我们有理由假设,上述静态和动态结构可以存在于由碳、硼和其他原子组成的真实单原子链中。

英文摘要:

In strained monoatomic chains with Lennard-Jones interactions, we revealed a stable static non-homogeneous structure appearing as a result of a certain phase transition. Positions of individual particles in this structure form an exact arithmetic progression whose difference depends on the value of the strain. For N-particle chain, this structure is characterized by one long and N-1 short interatomic distances (bonds). In the vicinity of the static structure, we found discrete breathers of new type which essentially differ from the traditional breathers in the form of Sievers-Takeno and Page modes. It is well known that these modes possess some staggered structures and demonstrate exponential decay of the particle amplitudes from the core to their tails. In contrast to such properties, our breathers are characterised by smooth decay and amplitudes of the particles form approximately a decreasing arithmetic progression. Core of these breathers is located on two particles with long bond in static structure. Our breathers demonstrate soft type of nonlinearity (the frequency decreases with increasing of amplitudes) and they are stable dynamical objects for amplitudes up to 20%-30% of interparticle distance of the strained equidistant chain. For infinitely small amplitudes these breathers tend to the above described static non-homogeneous structure. We studied dependence of their properties on amplitude, strain and the number of particles in the chain. There exist a reason to suppose that the above static and dynamical structures can exist in real monoatomic chains consisting of carbon, boron, and other atoms.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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