Density of excess modes below the first phonon mode in four-dimensional glasses  

作　　者：王利近 胥鼎 张世允 Lijin Wang;Ding Xu;Shiyun Zhang(School of Physics and Optoelectronic Engineering,Anhui University,Hefei 230601,China;Department of Physics,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]School of Physics and Optoelectronic Engineering,Anhui University,Hefei 230601,China [2]Department of Physics,University of Science and Technology of China,Hefei 230026,China

出　　处：《Chinese Physics B》2024年第7期483-489,共7页中国物理B（英文版）

基　　金：the support from the National Natural Science Foundation of China(Grant Nos.12374202 and 12004001);Anhui Projects(Grant Nos.2022AH020009,S020218016,and Z010118169);Hefei City(Grant No.Z020132009)。

摘　　要：Glasses are known to possess low-frequency excess modes beyond the Debye prediction.For decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law scaling:D(ω)~ω~γ.However,it remains debated on the value of γ at low frequencies below the first phonon-like mode in finitesize glasses.Early simulation studies reported γ=4 at low frequencies in two-(2D),three-(3D),and four-dimensional(4D)glasses,whereas recent observations in 2D and 3D glasses suggested γ=3.5 in a lower-frequency regime.It is uncertain whether the low-frequency scaling of D(ω)~ω^(3.5) could be generalized to 4D glasses.Here,we conduct numerical simulation studies of excess modes at frequencies below the first phonon-like mode in 4D model glasses.It is found that the system size dependence of D(ω) below the first phonon-like mode varies with spatial dimensions:D(ω) increases in2D glasses but decreases in 3D and 4D glasses as the system size increases.Furthermore,we demonstrate that the ω^(3.5)scaling,rather than the ω~4 scaling,works in the lowest-frequency regime accessed in 4D glasses,regardless of interaction potentials and system sizes examined.Therefore,our findings in 4D glasses,combined with previous results in 2D and 3D glasses,suggest a common low-frequency scaling of D(ω)~ ω^3.5) below the first phonon-like mode across different spatial dimensions,which would inspire further theoretical studies.

关 键 词：vibrational density of states excess modes four-dimensional glasses SCALING computer simulation 

分 类 号：O469[理学—凝聚态物理]