中国物理B ›› 2014, Vol. 23 ›› Issue (7): 76301-076301.doi: 10.1088/1674-1056/23/7/076301
• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇 下一篇
张国华a, 孙其诚b, 石志萍a, 冯旭a, 顾强a, 金峰b
Zhang Guo-Hua (张国华)a, Sun Qi-Cheng (孙其诚)b, Shi Zhi-Ping (石志萍)a, Feng Xu (冯旭)a, Gu Qiang (顾强)a, Jin Feng (金峰)b
摘要: Two-dimensional disordered granular assemblies composed of 2048 polydispersed frictionless disks are simulated using the discrete element method. The height of the first peak of the pair correlation function, g1, the local and global bond orientational parameters ψ6l and ψ6g, and the fluctuations of these parameters decrease with increasing polydispersity s, implying the transition from a polycrystalline state to an amorphous state in the system. As s increases, the peak position of the boson peak ωBP shifts towards a lower frequency and the intensity of the boson peak D(ωBP)/ωBP increases, indicating that the position and the strength of the boson peak are controlled by the polydispersity of the system. Moreover, the inverse of the boson peak intensity ωBP/D(ωBP), the shear modulus G, and the basin curvature SIS all have a similar dependence on s, implying that the s dependence of the vibrational density of states at low frequencies likely originates from the s dependence of the basin curvature.
中图分类号: (Vibrational states in disordered systems)