In this paper, we apply the K-theory scheme of classifying the topological insulators/superconductors to classify the topological classes of the massive multi-flavor fermions in anti-de Sitter(Ad S) space. In the cont...In this paper, we apply the K-theory scheme of classifying the topological insulators/superconductors to classify the topological classes of the massive multi-flavor fermions in anti-de Sitter(Ad S) space. In the context of Ad S/conformal field theory(CFT) correspondence, the multi-flavor fermionic mass matrix is dual to the pattern of operator mixing in the boundary CFT. Thus, our results classify the possible patterns of operator mixings among fermionic operators in the holographic CFT.展开更多
Electronic regulation of two-dimensional(2 D)transition metal dichalcogenides(TMDCs)is a crucial step towards next-generation optoelectronics and electronics.Here,we demonstrate controllable and selective-area defect ...Electronic regulation of two-dimensional(2 D)transition metal dichalcogenides(TMDCs)is a crucial step towards next-generation optoelectronics and electronics.Here,we demonstrate controllable and selective-area defect engineering in 2D molybdenum disulfide(MoS_(2))using a focused ion beam with a low-energy gallium ion(Ga^(+))source.We find that the surface defects of MoS_(2)can be tuned by the precise control of ion energy and dose.Furthermore,the fieldeffect transistors based on the monolayer MoS_(2)show a significant threshold voltage modulation over 70 V after Ga+irradiation.First-principles calculations reveal that the Ga impurities in the monolayer MoS_(2)introduce a defect state near the Fermi level,leading to a shallow acceptor level of 0.25 eV above the valence band maximum.This defect engineering strategy enables direct writing of complex pattern at the atomic length scale in a controlled and facile manner,tailoring the electronic properties of 2D TMDCs for novel devices.展开更多
基金supported by Taiwan’s Ministry of Science and Technology(Mo ST)Grants(100-2811-M-003-011 and 100-2918-I-003-008)
文摘In this paper, we apply the K-theory scheme of classifying the topological insulators/superconductors to classify the topological classes of the massive multi-flavor fermions in anti-de Sitter(Ad S) space. In the context of Ad S/conformal field theory(CFT) correspondence, the multi-flavor fermionic mass matrix is dual to the pattern of operator mixing in the boundary CFT. Thus, our results classify the possible patterns of operator mixings among fermionic operators in the holographic CFT.
基金supported by Fujian Minjiang Distinguished Scholar Programthe Department of Science and Technology of Fujian Province(2020J01704 and 2019L3008)the Scientific Research Foundation from Jimei University(ZP2020066 and ZP2020065)。
文摘Electronic regulation of two-dimensional(2 D)transition metal dichalcogenides(TMDCs)is a crucial step towards next-generation optoelectronics and electronics.Here,we demonstrate controllable and selective-area defect engineering in 2D molybdenum disulfide(MoS_(2))using a focused ion beam with a low-energy gallium ion(Ga^(+))source.We find that the surface defects of MoS_(2)can be tuned by the precise control of ion energy and dose.Furthermore,the fieldeffect transistors based on the monolayer MoS_(2)show a significant threshold voltage modulation over 70 V after Ga+irradiation.First-principles calculations reveal that the Ga impurities in the monolayer MoS_(2)introduce a defect state near the Fermi level,leading to a shallow acceptor level of 0.25 eV above the valence band maximum.This defect engineering strategy enables direct writing of complex pattern at the atomic length scale in a controlled and facile manner,tailoring the electronic properties of 2D TMDCs for novel devices.
