The family of vanadium chalcogenides with variable stoichiometry and abundant crystallographic structures are promising platforms for realizing exotic emergent phenomena.Here,we report on a novel two-dimensional(2D)te...The family of vanadium chalcogenides with variable stoichiometry and abundant crystallographic structures are promising platforms for realizing exotic emergent phenomena.Here,we report on a novel two-dimensional(2D)tetragonal structure of vanadium telluride(VTe)grown by molecular beam epitaxy.The atomic structures and electronic properties are revealed by scanning tunneling microscopy and first-principles calculations.Different from the hexagonal or trigonal lattices of 2D VTe_(2),the 2D VTe with a V:Te ratio of 1:1 exhibits an uncommon square lattice.Non-zero differential conductivity at the Fermi energy detected by scanning tunneling spectroscopy reveals the metallic feature of VTe.Meanwhile,Friedel oscillations are observed near chiral point defects and domain walls,illustrating the itinerant nature of the electrons close to the Fermi energy.Our firstprinciples structure searches identify a 2D body-centered cubic(bcc)-like structure with a favorable formation energy to be the candidate of the metallic phase of the tetragonal VTe obtained experimentally.Based on our calculations the 2D bcc-like structure possesses a strong 2D antiferromagnetic order.Our work enriches the family of vanadium chalcogenides and provides a possible 2D antiferromagnetic material for fabricating advanced spintronic devices.展开更多
基金the National Natural Science Foundation of China(Nos.11974431,92165204,and 11832019)Guangdong Major Project of Basic and Applied Basic Research(No.2021B0301030002).
文摘The family of vanadium chalcogenides with variable stoichiometry and abundant crystallographic structures are promising platforms for realizing exotic emergent phenomena.Here,we report on a novel two-dimensional(2D)tetragonal structure of vanadium telluride(VTe)grown by molecular beam epitaxy.The atomic structures and electronic properties are revealed by scanning tunneling microscopy and first-principles calculations.Different from the hexagonal or trigonal lattices of 2D VTe_(2),the 2D VTe with a V:Te ratio of 1:1 exhibits an uncommon square lattice.Non-zero differential conductivity at the Fermi energy detected by scanning tunneling spectroscopy reveals the metallic feature of VTe.Meanwhile,Friedel oscillations are observed near chiral point defects and domain walls,illustrating the itinerant nature of the electrons close to the Fermi energy.Our firstprinciples structure searches identify a 2D body-centered cubic(bcc)-like structure with a favorable formation energy to be the candidate of the metallic phase of the tetragonal VTe obtained experimentally.Based on our calculations the 2D bcc-like structure possesses a strong 2D antiferromagnetic order.Our work enriches the family of vanadium chalcogenides and provides a possible 2D antiferromagnetic material for fabricating advanced spintronic devices.
