Bound states in the continuum(BICs) are spatially localized states with energy embedded in the continuum spectrum of extended states. The combination of BICs physics and nontrivial band topology theory givs rise to to...Bound states in the continuum(BICs) are spatially localized states with energy embedded in the continuum spectrum of extended states. The combination of BICs physics and nontrivial band topology theory givs rise to topological BICs, which are robust against disorders and meanwhile, the merit of conventional BICs is attracting wide attention recently. Here, we report valley edge states as topological BICs, which appear at the domain wall between two distinct valley topological phases. The robustness of such BICs is demonstrated. The simulations and experiments show great agreement. Our findings of valley related topological BICs shed light on both BICs and valley physics, and may foster innovative applications of topological acoustic devices.展开更多
When an electron with negative charge-e is incident from a normal metal to an interface with a superconductor,it may be reflected as a hole with positive charge e at the interface.In such a way,a pair of electrons can...When an electron with negative charge-e is incident from a normal metal to an interface with a superconductor,it may be reflected as a hole with positive charge e at the interface.In such a way,a pair of electrons can be transferred to the superconductor and form a Cooper pair.This process of electron-hole conversion is called Andreev reflection(AR)[1].展开更多
The study of topological semimetals hosting spin-1 Weyl points(WPs)beyond Dirac points and WPs has attracted a great deal of attention.However,a spin-1 Weyl semimetal that exclusively possesses spin-1 WPs in a clean f...The study of topological semimetals hosting spin-1 Weyl points(WPs)beyond Dirac points and WPs has attracted a great deal of attention.However,a spin-1 Weyl semimetal that exclusively possesses spin-1 WPs in a clean frequency window without being shadowed by any other nodal points is yet to be discovered.This study reports a spin-1 Weyl semimetal in a phononic crystal.Its spin-1 WPs are touched by two linear dispersions and an additional flat band and carry monopole charges(-2,0,2)or(2,0,-2)for the three bands from the bottom to the top.They result in double Fermi arcs,which occur between the first and second bands,as well as between the second and third bands.Further robust propagation is observed against the multiple joints and topological negative refraction of the acoustic surface arc wave.The results of this study create the basis for the exploration of the unusual properties of spin-1 Weyl physics on a macroscopic scale.展开更多
基金supported by the National Key R&D Program of China (2022YFA1404500,and 2022YFA1404900)National Natural Science Foundation of China (12074128,12004286,12104347,12222405,12374419,and 12374409)Guangdong Basic and Applied Basic Research Foundation (2021B1515020086,and 2022B1515020102)。
文摘Bound states in the continuum(BICs) are spatially localized states with energy embedded in the continuum spectrum of extended states. The combination of BICs physics and nontrivial band topology theory givs rise to topological BICs, which are robust against disorders and meanwhile, the merit of conventional BICs is attracting wide attention recently. Here, we report valley edge states as topological BICs, which appear at the domain wall between two distinct valley topological phases. The robustness of such BICs is demonstrated. The simulations and experiments show great agreement. Our findings of valley related topological BICs shed light on both BICs and valley physics, and may foster innovative applications of topological acoustic devices.
基金supported by the National Key R&D Program of China(Grant Nos.2022YFA1404900,2022YFA1404500,and 2018YFA0305800)the National Natural Science Foundation of China(Grant Nos.11890701,11974120,11974005,12074128,and 12222405)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2019B151502012,2021B1515020086,and 2022B1515020102).
基金supported by the National Natural Science Foundation of China(11890701,11974120,11974005,12074128,12074232,12125406,and 12174455)the National Key R&D Program of China(2018YFA0305800)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(2019B151502012,2021B1515020086,and 2021A1515010347)the Science and Technology Projects in Guangzhou(202102020960)。
文摘When an electron with negative charge-e is incident from a normal metal to an interface with a superconductor,it may be reflected as a hole with positive charge e at the interface.In such a way,a pair of electrons can be transferred to the superconductor and form a Cooper pair.This process of electron-hole conversion is called Andreev reflection(AR)[1].
基金supported by the National Key Research and Development Program of China(Grant No.2018FYA0305800)the National Natural Science Foundation of China(Grant Nos.11890701,11704128,11774275,11804101,11974005,and 11974120)+2 种基金the Guangdong Innovative and Entrepreneurial Research Team Program(Grant No.2016ZT06C594)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2019B151502012)the Fundamental Research Funds for the Central Universities(Grant Nos.2018MS93,2019JQ07,and 2019ZD49)。
文摘The study of topological semimetals hosting spin-1 Weyl points(WPs)beyond Dirac points and WPs has attracted a great deal of attention.However,a spin-1 Weyl semimetal that exclusively possesses spin-1 WPs in a clean frequency window without being shadowed by any other nodal points is yet to be discovered.This study reports a spin-1 Weyl semimetal in a phononic crystal.Its spin-1 WPs are touched by two linear dispersions and an additional flat band and carry monopole charges(-2,0,2)or(2,0,-2)for the three bands from the bottom to the top.They result in double Fermi arcs,which occur between the first and second bands,as well as between the second and third bands.Further robust propagation is observed against the multiple joints and topological negative refraction of the acoustic surface arc wave.The results of this study create the basis for the exploration of the unusual properties of spin-1 Weyl physics on a macroscopic scale.
