Stress fluctuations and elasticity in one- and two-component cubic crystals

ABSTRACT

The elastic constants of the Lennard-Jones system and a binary repulsive particle system (in 1:13 composition) obeying the Weeks-Chandler-Andersen (WCA) potential (WCA2-AB13 system) have been computed using the stress fluctuation formalism by equilibrium molecular dynamics simulations. The systems are under finite fixed pressures. The evolution of the elastic moduli as a function of the temperature is characterised. In both systems, the melting transition is signalled by a jump of the shear modulus, in consistence with the behaviour of the specific volume. At zero temperature, while the elasticity is totally affine for the Lennard-Jones face-centered cubic (fcc) crystal, it clearly contains a non-affine part for the AB13 cubic superlattice. The evolution of the non-affine elasticity as a function of the temperature is investigated, and its behaviour is compared to that of a typical glass-former.

KEYWORDS:

• Elasticity
• simulations
• stress-fluctuations

Acknowledgments

The computer resources from the SIMPA centre at the University of Lorraine (Metz) are gratefully acknowledged. D. Li thanks the support by the Chinese Scholarship Council under a PhD grant.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Chinese Scholarship Council.