Disordered hyperuniformity(DHU)is a recently discovered novel state of amorphous systems characterized by strongly suppressed density fluctuations at large length scales as in crystalline materials,which offers great ...Disordered hyperuniformity(DHU)is a recently discovered novel state of amorphous systems characterized by strongly suppressed density fluctuations at large length scales as in crystalline materials,which offers great potential for achieving unusual mechanical,electronic,and photonic properties.However,despite the fundamental and technological importance of thermal transport in amorphous solids,the effect of DHU remains largely unexplored.Here,we theoretically study thermal transport in a class of two-dimensional DHU materials—monolayer amorphous carbon(MAC).Beginning with a perfect graphene lattice,we continuously apply Stone-Wales transformations to generate a series of MAC models with varied degrees of disorder and defects,which are quantified through comprehensive structural analysis including the so-called hyperuniformity index(H),where a smaller H indicates a higher degree of hyperuniformity.Subsequently,we conduct molecular dynamics simulations to obtain the thermal conductivity(κ).A significant correlation between the thermal transport behavior and degree of hyperuniformity is observed,with the room-temperatureκdecreasing from 26.3 to 5.3 W m^(-1)K^(-1)while H is tuned from 0.0004 to 0.024.Remarkably,two distinct transport regimes are identified,including a nearly-DHU regime at small H(<0.005)whereκdrops sharply and a non-DHU region at larger H whereκbecomes relatively flat.Mode-resolved analysis reveals longer lifetime and higher participation ratio for the heat carriers in nearly-DHU MAC,implying that the hidden long-range correlations could support extended modes that enhance transport.Our work highlights the impact of DHU on the thermal properties of amorphous materials and represents a conceptual advancement that is worthy of future exploration.展开更多
The deformation-loss of waveguides is a critical element that hinders the application range.Crystal waveguides have been studied for the construction of anti-deformation waveguides.However,the bandwidth of crystal wav...The deformation-loss of waveguides is a critical element that hinders the application range.Crystal waveguides have been studied for the construction of anti-deformation waveguides.However,the bandwidth of crystal waveguides is strictly reliant on the crystal lattice's periodicity.In case the deformation is extreme,and the crystal lattice is drastically altered,the bandwidth will be significantly diminished,and transmission loss will surge.Here,we report an elastic waveguide design based on the disordered hyperuniform(DH)distribution with as low as about 20%bandwidth loss under deformations with an average strain of approximately 10%.In contrast,the phononic crystal elastic waveguide(PCEWG)exhibits an average reduction of 50%for the same degree of deformation.This is demonstrated through simulations under four different deformation conditions:firstorder bending,second-order bending,compressing and stretching.A theoretical explanation is provided through the calculation of structural factors.Choosing soft materials as the matrix and explaining the mechanism through elastic waves,we present a promising avenue for communication through the human body.展开更多
In recent years,there has been growing interest in the study of chiral active materials,which consist of building blocks that show active dynamics featuring chiral symmetry breaking,e.g.,particles that rotate in a com...In recent years,there has been growing interest in the study of chiral active materials,which consist of building blocks that show active dynamics featuring chiral symmetry breaking,e.g.,particles that rotate in a common direction.These materials exhibit fascinating phenomena such as odd viscosity,odd diffusivity,active turbulence in fluids,vivid dislocation dynamics or odd elasticity in crystals or elastic materials,and hyperuniform states.The systematic study of soft chiral active matter systems is relatively new,starting around 2017,but has already shown promising applications in robust cargo transport,segregation and mixing dynamics,or manipulation of metamaterials.In this review,we summarize recent experimental and theoretical advances in this field,highlighting the emergence of anti-symmetric and odd stresses and ensuring effects such as odd viscosity or topologically protected edge modes.We further discuss the underlying mechanisms and provide insights into the potential of chiral active matter for various applications.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1203100)the National Natural Science Foundation of China(Grant No.52076002)+1 种基金the High-performance Computing Platform of Peking Universitysupport from the New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘Disordered hyperuniformity(DHU)is a recently discovered novel state of amorphous systems characterized by strongly suppressed density fluctuations at large length scales as in crystalline materials,which offers great potential for achieving unusual mechanical,electronic,and photonic properties.However,despite the fundamental and technological importance of thermal transport in amorphous solids,the effect of DHU remains largely unexplored.Here,we theoretically study thermal transport in a class of two-dimensional DHU materials—monolayer amorphous carbon(MAC).Beginning with a perfect graphene lattice,we continuously apply Stone-Wales transformations to generate a series of MAC models with varied degrees of disorder and defects,which are quantified through comprehensive structural analysis including the so-called hyperuniformity index(H),where a smaller H indicates a higher degree of hyperuniformity.Subsequently,we conduct molecular dynamics simulations to obtain the thermal conductivity(κ).A significant correlation between the thermal transport behavior and degree of hyperuniformity is observed,with the room-temperatureκdecreasing from 26.3 to 5.3 W m^(-1)K^(-1)while H is tuned from 0.0004 to 0.024.Remarkably,two distinct transport regimes are identified,including a nearly-DHU regime at small H(<0.005)whereκdrops sharply and a non-DHU region at larger H whereκbecomes relatively flat.Mode-resolved analysis reveals longer lifetime and higher participation ratio for the heat carriers in nearly-DHU MAC,implying that the hidden long-range correlations could support extended modes that enhance transport.Our work highlights the impact of DHU on the thermal properties of amorphous materials and represents a conceptual advancement that is worthy of future exploration.
基金supported by the National Natural Science Foundation of China(Grant Nos.T2350001 and 52173280)China Postdoctoral Science Foundation(Grant No.2022M711256)。
文摘The deformation-loss of waveguides is a critical element that hinders the application range.Crystal waveguides have been studied for the construction of anti-deformation waveguides.However,the bandwidth of crystal waveguides is strictly reliant on the crystal lattice's periodicity.In case the deformation is extreme,and the crystal lattice is drastically altered,the bandwidth will be significantly diminished,and transmission loss will surge.Here,we report an elastic waveguide design based on the disordered hyperuniform(DH)distribution with as low as about 20%bandwidth loss under deformations with an average strain of approximately 10%.In contrast,the phononic crystal elastic waveguide(PCEWG)exhibits an average reduction of 50%for the same degree of deformation.This is demonstrated through simulations under four different deformation conditions:firstorder bending,second-order bending,compressing and stretching.A theoretical explanation is provided through the calculation of structural factors.Choosing soft materials as the matrix and explaining the mechanism through elastic waves,we present a promising avenue for communication through the human body.
基金the National Natural Sience Foundation of China for supporting this project within the Research Fund for International Young Scientists(12350410368)financial support from the Natural Science Foundation of Guangdong Province(2024A1515011343)the Key Project of Guangdong Provincial Department of Education(2023ZDZX3021)
文摘In recent years,there has been growing interest in the study of chiral active materials,which consist of building blocks that show active dynamics featuring chiral symmetry breaking,e.g.,particles that rotate in a common direction.These materials exhibit fascinating phenomena such as odd viscosity,odd diffusivity,active turbulence in fluids,vivid dislocation dynamics or odd elasticity in crystals or elastic materials,and hyperuniform states.The systematic study of soft chiral active matter systems is relatively new,starting around 2017,but has already shown promising applications in robust cargo transport,segregation and mixing dynamics,or manipulation of metamaterials.In this review,we summarize recent experimental and theoretical advances in this field,highlighting the emergence of anti-symmetric and odd stresses and ensuring effects such as odd viscosity or topologically protected edge modes.We further discuss the underlying mechanisms and provide insights into the potential of chiral active matter for various applications.
