MICAtronics, based on the functional oxide/mica heterostructures, has recently attracted much attention due to its potential applications in transparent, flexible electronics and devices. However, the weak van der Waa...MICAtronics, based on the functional oxide/mica heterostructures, has recently attracted much attention due to its potential applications in transparent, flexible electronics and devices. However, the weak van der Waals interaction decreases the tolerable lattice mismatch and thus limits the species of function oxides that are able to be epitaxially grown on mica. We successfully fabricate relatively high-quality epitaxial anatase TiO2 thin films on mica substrates. Structural analyses reveal that the carefully chosen growth temperature(650℃) and suitable crystalline phase(anatase phase) of TiO2 are the key issues for this van der Waals epitaxy. Moreover, as a buffer layer, the TiO2 layer successfully suppresses the decomposition of BiFeO3 and the difficulty of epitaxial growth of BiFeO3 is decreased. Therefore, relatively high-quality anatase TiO2 is proved to be an effective buffer layer for fabricating more functional oxides on mica.展开更多
Epitaxial graphene grown on silicon carbide(Si C/graphene)is a promising solution for achieving a highprecision quantum Hall resistance standard.Previous research mainly focused on the quantum resistance metrology of ...Epitaxial graphene grown on silicon carbide(Si C/graphene)is a promising solution for achieving a highprecision quantum Hall resistance standard.Previous research mainly focused on the quantum resistance metrology of n-type Si C/graphene,while a comprehensive understanding of the quantum resistance metrology behavior of graphene with different doping types is lacking.Here,we fabricated both n-and p-type Si C/graphene devices via polymer-assisted molecular adsorption and conducted systematic magneto-transport measurements in a wide parameter space of carrier density and temperature.It is demonstrated that n-type devices show greater potential for development of quantum resistance metrology compared with p-type devices,as evidenced by their higher carrier mobility,lower critical magnetic field for entering quantized Hall plateaus,and higher robustness of the quantum Hall effect against thermal degeneration.These discrepancies can be reasonably attributed to the weaker scattering from molecular dopants for n-type devices,which is further supported by the analyses on the quantum interference effect in multiple devices.These results enrich our understanding of the charged impurity on electronic transport performance of graphene and,more importantly,provide a useful reference for future development of graphene-based quantum resistance metrology.展开更多
The reconstruction process of the Si(111)√3 ×√3 R30°-Ag surface is studied by using a scanning tunnelling microscope at 78K.By applying a strong interaction between the tip and the surface,a tip-induced re...The reconstruction process of the Si(111)√3 ×√3 R30°-Ag surface is studied by using a scanning tunnelling microscope at 78K.By applying a strong interaction between the tip and the surface,a tip-induced reconstruction corresponding to the mergence of two Si(111)√3 ×√3 R30°-Ag domains is observed.Based on the inequivalent trimers(IET)model,this reconstruction process is attributed to a transition between the clockwise and counterclockwise IET domains.With this transition,the honeycomb-chained-trimer Si(111)√3 ×√3 R30°-Ag anti-phase boundary disappears and changes to the IET structure.展开更多
基金Supported by National Basic Research Program of China(2014CB 921102)National Natural Science Foundation of China(11434009,11374279,11461161009)+1 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB01020000)the Fundamental Research Funds for the Central Universities(WK2030020027)
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFA0300102the National Natural Science Foundation of China under Grant Nos 11675179,11434009 and 11374010the Fundamental Research Funds for the Central Universities under Grant No WK2340000065
文摘MICAtronics, based on the functional oxide/mica heterostructures, has recently attracted much attention due to its potential applications in transparent, flexible electronics and devices. However, the weak van der Waals interaction decreases the tolerable lattice mismatch and thus limits the species of function oxides that are able to be epitaxially grown on mica. We successfully fabricate relatively high-quality epitaxial anatase TiO2 thin films on mica substrates. Structural analyses reveal that the carefully chosen growth temperature(650℃) and suitable crystalline phase(anatase phase) of TiO2 are the key issues for this van der Waals epitaxy. Moreover, as a buffer layer, the TiO2 layer successfully suppresses the decomposition of BiFeO3 and the difficulty of epitaxial growth of BiFeO3 is decreased. Therefore, relatively high-quality anatase TiO2 is proved to be an effective buffer layer for fabricating more functional oxides on mica.
基金supported by the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-046)the National Natural Science Foundation of China(Grant Nos.92165201,11974324,12104435)+4 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302800)the Anhui Initiative in Quantum Information Technologies(Grant No.AHY170000)Hefei Science Center CAS(Grant No.2020HSC-UE014)the Fundamental Research Funds for the Central Universities(Grant Nos.WK3510000013 and WK2310000104)supported by USTC Tang Scholar。
文摘Epitaxial graphene grown on silicon carbide(Si C/graphene)is a promising solution for achieving a highprecision quantum Hall resistance standard.Previous research mainly focused on the quantum resistance metrology of n-type Si C/graphene,while a comprehensive understanding of the quantum resistance metrology behavior of graphene with different doping types is lacking.Here,we fabricated both n-and p-type Si C/graphene devices via polymer-assisted molecular adsorption and conducted systematic magneto-transport measurements in a wide parameter space of carrier density and temperature.It is demonstrated that n-type devices show greater potential for development of quantum resistance metrology compared with p-type devices,as evidenced by their higher carrier mobility,lower critical magnetic field for entering quantized Hall plateaus,and higher robustness of the quantum Hall effect against thermal degeneration.These discrepancies can be reasonably attributed to the weaker scattering from molecular dopants for n-type devices,which is further supported by the analyses on the quantum interference effect in multiple devices.These results enrich our understanding of the charged impurity on electronic transport performance of graphene and,more importantly,provide a useful reference for future development of graphene-based quantum resistance metrology.
基金Supported by the National Natural Science Foundation of China under Grant Nos.5997203 and G1999075305the Hong Kong'Qiu Shi'Foundation.
文摘The reconstruction process of the Si(111)√3 ×√3 R30°-Ag surface is studied by using a scanning tunnelling microscope at 78K.By applying a strong interaction between the tip and the surface,a tip-induced reconstruction corresponding to the mergence of two Si(111)√3 ×√3 R30°-Ag domains is observed.Based on the inequivalent trimers(IET)model,this reconstruction process is attributed to a transition between the clockwise and counterclockwise IET domains.With this transition,the honeycomb-chained-trimer Si(111)√3 ×√3 R30°-Ag anti-phase boundary disappears and changes to the IET structure.
