Enhanced mobility of high-frequency discrete breathers in a monatomic chain with odd anharmonicity

TL;DR

This paper investigates how odd anharmonicity in monatomic chains enhances the mobility of high-frequency discrete breathers, enabling longer propagation distances and stability inversion, with implications for nonlinear lattice dynamics.

Contribution

It demonstrates that odd anharmonicity significantly increases breather mobility and causes stability inversion, which was not previously understood in such systems.

Findings

Odd anharmonicity sharply increases breather propagation distance.

Correctly chosen fifth anharmonicity inverts breather stability.

Discrete breathers exhibit low-radiative propagation along the chain.

Abstract

The mobility of high-frequency discrete breathers in monatomic chains with nonlinear interatomic potentials of the nearest neighbours is considered. It was found that the odd (cubic and fifth) anharmonicity strongly affects the mobility of breathers, sharply increasing the distance that it propagates without being trapped. It was also found that the correctly chosen fifth anharmonicity leads to an inversion of stability between the bond-centred and site-centers breathers and to the low-radiative propagation of discrete breathers along the chain.