Combining logical function and memory characteristics of transistors is an ideal strategy for enhancing computational efficiency of transistor devices.Here,we rationally design a tri-gate two-dimensional(2D)ferroelect...Combining logical function and memory characteristics of transistors is an ideal strategy for enhancing computational efficiency of transistor devices.Here,we rationally design a tri-gate two-dimensional(2D)ferroelectric van der Waals heterostructures device based on copper indium thiophosphate(CuInP_(2)S_(6))and few layers tungsten disulfide(WS_(2)),and demonstrate its multi-functional applications in multi-valued state of data,non-volatile storage,and logic operation.By co-regulating the input signals across the tri-gate,we show that the device can switch functions flexibly at a low supply voltage of 6 V,giving rise to an ultra-high current switching ratio of 107 and a low subthreshold swing of 53.9 mV/dec.These findings offer perspectives in designing smart 2D devices with excellent functions based on ferroelectric van der Waals heterostructures.展开更多
Vanadium dichalcogenides have attracted increasing interests for the charge density wave phenomena and possible ferromagnetism.Here,we report on the multiphase behavior and gap opening in monolayer VTe2 grown by molec...Vanadium dichalcogenides have attracted increasing interests for the charge density wave phenomena and possible ferromagnetism.Here,we report on the multiphase behavior and gap opening in monolayer VTe2 grown by molecular beam epitaxy.Scanning tunneling microscopy(STM)and spectroscopy study revealed the(4×4)metallic and gapped(2√3×2√3)charge-density wave(CDW)phases with an energy gap of≈40 meV.Through the in-plane condensation of vanadium atoms,the typical star-of-David clusters and truncated triangle-shaped clusters are formed in the(4×4)and(2√3×2√3)phases respectively,resulting in different surface morphologies and electronic structures as confirmed by density functional theory(DFT)calculations with on-site Coulomb repulsion.The CDW-driven reorganization of the atomic structure weakens the ferromagnetic superexchange coupling and strengthens the antiferromagnetic exchange coupling on the contrary,suppressing the long-range magnetic order in monolayer VTe2.The electron correlation is found to be important to explain the gap opening in the(2√3×2√3)phase.展开更多
基金supported by the National Natural Science Foundation of China(No.62104073)the China Postdoctoral Science Foundation(No.2021M691088)+1 种基金the Pearl River Talent Recruitment Program(No.2019ZT08X639)Z.C.W.acknowledges the European Research Executive Agency(Project 101079184-FUNLAYERS).
文摘Combining logical function and memory characteristics of transistors is an ideal strategy for enhancing computational efficiency of transistor devices.Here,we rationally design a tri-gate two-dimensional(2D)ferroelectric van der Waals heterostructures device based on copper indium thiophosphate(CuInP_(2)S_(6))and few layers tungsten disulfide(WS_(2)),and demonstrate its multi-functional applications in multi-valued state of data,non-volatile storage,and logic operation.By co-regulating the input signals across the tri-gate,we show that the device can switch functions flexibly at a low supply voltage of 6 V,giving rise to an ultra-high current switching ratio of 107 and a low subthreshold swing of 53.9 mV/dec.These findings offer perspectives in designing smart 2D devices with excellent functions based on ferroelectric van der Waals heterostructures.
基金D.Y.Z.thanks the financial support from the National Natural Science Foundation Program of China(Nos.11974431 and 11832019)the Guangzhou Science and Technology Project(No.201707020002)+4 种基金C.W.W.and D.X.Y.thank the support from The National Key Research and Development Program of China(Nos.2017YFA0206203 and 2018YFA0306001)the National Natural Science Foundation Program of China(No.11974432)Guangdong Basic and Applied Basic Research Foundation(No.2019A1515011337)Leading Talent Program of Guangdong Special ProjectsThe computation part of the work was supported by National Supercomputer Center in Guangzhou,China.
文摘Vanadium dichalcogenides have attracted increasing interests for the charge density wave phenomena and possible ferromagnetism.Here,we report on the multiphase behavior and gap opening in monolayer VTe2 grown by molecular beam epitaxy.Scanning tunneling microscopy(STM)and spectroscopy study revealed the(4×4)metallic and gapped(2√3×2√3)charge-density wave(CDW)phases with an energy gap of≈40 meV.Through the in-plane condensation of vanadium atoms,the typical star-of-David clusters and truncated triangle-shaped clusters are formed in the(4×4)and(2√3×2√3)phases respectively,resulting in different surface morphologies and electronic structures as confirmed by density functional theory(DFT)calculations with on-site Coulomb repulsion.The CDW-driven reorganization of the atomic structure weakens the ferromagnetic superexchange coupling and strengthens the antiferromagnetic exchange coupling on the contrary,suppressing the long-range magnetic order in monolayer VTe2.The electron correlation is found to be important to explain the gap opening in the(2√3×2√3)phase.
