Epitaxial Growth of Honeycomb Monolayer CuSe with Dirac Nodal Line Fermions

Gao, Lei; Sun, Jianing; Lu, Jianchen; Li, Hang; Qian, Kai; Zhang, Shuai; Zhang, Yuyang; Qian, Tian; Ding, Hong; Lin, Xiuping; Du, Shixuan

doi:10.1002/adma.201707055

Cited by 124 publications

(115 citation statements)

References 45 publications

(42 reference statements)

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“…Such structural imperfections and the polarization of the material by the pyridine moieties facilitate a chemical functionalization by oxidizing over H 2 SO 4 /H 2 O 2 (1:1). Such reactivity has previously been reported for modification of carbon fibers to increase their interaction with polymeric matrices …”

Section: Resultssupporting

confidence: 53%

Bioinspired Electro‐Organocatalytic Material Efficient for Hydrogen Production

Moral

Call

Franco

et al. 2018

Chemistry A European J

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Commercial carbon fibers can be used as electrodes with high conductive surfaces in reduced devices. Oxidative treatment of such electrodes results in a chemically robust material with high catalytic activity for electrochemical proton reduction, enabling the measurement of quantitative faradaic yields (>95 %) and high current densities. Combination of experiments and DFT calculations reveals that the presence of carboxylic groups triggers such electrocatalytic activity in a bioinspired manner. Analogously to the known Hantzsch esters, the oxidized carbon fiber material is able to transfer hydrides, which can react with protons, generating H , or with organic substrates resulting in their hydrogenation. A plausible mechanism is proposed based on DFT calculations on model systems.

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Section: Resultssupporting

confidence: 53%

Bioinspired Electro‐Organocatalytic Material Efficient for Hydrogen Production

Moral

Call

Franco

et al. 2018

Chemistry A European J

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“…When the self-consistence convergence of computation fails for checkerboard case, stripe configuration is also considered (see Figure S1 for details about magnetic configurations 39 ). As shown in Figure 2c, 2d, 2e, there are 56 (33) FM (AFM) monolayers, consisting of 21 (12) binary, 27 (12) ternary, 6 (7) quaternary and 2 (2) quinary compounds. Binary FM monolayers are mostly halides, while chalcogenides dominate ternary magnetic monolayers.…”

Section: / 12mentioning

confidence: 99%

Screening Magnetic Two-Dimensional Atomic Crystals with Nontrivial Electronic Topology

Liu

Sun

Liu

et al. 2018

J. Phys. Chem. Lett.

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To date only a few two-dimensional (2D) magnetic crystals were experimentally confirmed, such as CrI 3 and CrGeTe 3 , all with very low Curie temperatures (T C ). High-throughput first-principles screening over a large set of materials yields 89 magnetic monolayers including 56 ferromagnetic (FM) and 33 antiferromagnetic compounds.Among them, 24 FM monolayers are promising candidates possessing T C higher than that of CrI 3 . High T C monolayers with fascinating electronic phases are identified: (i) quantum anomalous and valley Hall effects coexist in a single material RuCl 3 or VCl 3 , leading to a valley-polarized quantum anomalous Hall state; (ii) TiBr 3 , Co 2 NiO 6 and V 2 H 3 O 5 are revealed to be half-metals. More importantly, a new type of fermion dubbed type-II Weyl ring is discovered in ScCl. Our work provides a database of 2D magnetic materials, which could guide experimental realization of high-temperature magnetic monolayers with exotic electronic states for future spintronics and quantum computing applications. KEYWORDS: Magnetic two-dimensional crystals, high throughput calculations, quantum anomalous Hall effect, valley Hall effect. 2 / 12The discovery of two-dimensional (2D) materials opens a new avenue with rich physics promising for applications in a variety of subjects including optoelectronics, valleytronics, and spintronics, many of which benefit from the emergence of Dirac/Weyl fermions. One example is transition-metal dichalcogenide (TMDC) monolayers, whose finite direct bandgap enable novel optoelectronic controls as well as valley-dependent phenomena, such as circular dichroism and valley Hall effect (VHE) 1-2 . Due to the equivalent occupation of K and K' valleys in TMDC materials, the VHE does not produce observable macroscopic Hall voltage. This is overcome in magnetic counterparts, resulted from time reversal symmetry breaking 3-8 .In contrast to fermions in nonmagnetic systems, such as massless Dirac fermions in borophene, black phosphorus, Cu 2 Si 9-13 , and massive Dirac fermions in graphene and bilayer bismuth 14-15 , few types of fermions in 2D magnetic systems are proposed, implying the scarcity of intrinsic magnetic 2D crystals. In particular, 2D magnets with massive Dirac fermions can support quantum anomalous Hall state leading to topologically protected spin current, promising for low-power-consumption devices. Unfortunately, the state is only realized in 2D materials with non-intrinsic magnetism at extremely low temperature (e.g. 30 mK for Cr-doped (Bi,Sb) 2 Te 3 thin film) [16][17][18][19][20][21][22] , hampering its extensive applications. Therefore, discovery of 2D magnets at an elevated temperature is of great importance, providing optimal platforms to enable realistic spintronic and quantum devices, as well as to realize new electronic states.To date 2D magnetic materials are limited to marginal modifications to existing compounds, for instance by: (i) adsorbing hydrogen on graphene 23 ; (ii) reconstructing surface/edge [24][25] ; or (iii) creating defects in MoS 2 n...

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“…On the other hand, Honeycomb-Kagome lattice Hg 3 As 2 [31], Lieb lattice BeH 2 and Be 2 C [32], single layer MX (M=Pd, Pt; X=S, Se, Te) [33], single layer B 2 C [34], 2D compounds X 2 Y (X=Ca, Sr and Ba; Y=As, Sb and Bi) [35], β 12 -borophene [36] and pentagonal group p-IVX 2 (IV=C, Si, Ge, Sn, Pb; X=S, Se, Te) [37] were predicted to be 2D node line semimetals, in which the conduction and valence bands touch near the Fermi level at extended loops. More intriguingly, single layer Cu 2 Si [38] and CuSe [39] have been experimentally demonstrated to be 2D node line semimetals. Up to now, single layer HfGeTe [40] have been theoretically proposed to be 2D Z 2 topological metal.…”

Section: Introductionmentioning

confidence: 99%

Topological node line semimetal state in two-dimensional tetragonal allotrope of Ge and Sn

Wang

Han

et al. 2019

New J. Phys.

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Realizing semimetal states in two-dimensional (2D) materials are of great importance for their future application in novel quantum devices at the nanoscale. Using first-principles calculations based on density functional theory, we propose a new 2D tetragonal allotrope of Ge and Sn, 2D T-Ge and T-Sn, which consists of repeated square and octagon rings. The calculated cohesive energy, ab initio molecular dynamic simulations and phonon dispersions indicate that 2D T-Ge and T-Sn are stable at room temperature and possibly synthesized in the experiments under appropriate growth conditions. In the absence of spin-orbital coupling (SOC), 2D T-Ge and T-Sn are node line semimetals and the nodal loop in 2D T-Ge and T-Sn are protected by the combination of the spatial inversion P and timereversal T symmetries. Remarkably, when SOC is included, 2D T-Ge and T-Sn are still node line semimetals although small gap is opened along the nodal loop, which are identified by nontrivial Z 2 invariant and topological edge states at the sample boundaries. Furthermore, our calculations show that node line semimetal states in 2D T-Ge and T-Sn are robust with the biaxial strains in the range of −3% to 3%. Our results provide a new 2D material platform for realization of 2D topological node line semimetals and innovative applications of topological node line semimetals.

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Epitaxial Growth of Honeycomb Monolayer CuSe with Dirac Nodal Line Fermions

Cited by 124 publications

References 45 publications

Bioinspired Electro‐Organocatalytic Material Efficient for Hydrogen Production

Bioinspired Electro‐Organocatalytic Material Efficient for Hydrogen Production

Screening Magnetic Two-Dimensional Atomic Crystals with Nontrivial Electronic Topology

Topological node line semimetal state in two-dimensional tetragonal allotrope of Ge and Sn

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