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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Guest-Free Monolayer Clathrate And Its Coexistence With Two-Dimensional High-Density Ice, Jaeil Bai, C. Austen Angell, Xiao Cheng Zeng
Guest-Free Monolayer Clathrate And Its Coexistence With Two-Dimensional High-Density Ice, Jaeil Bai, C. Austen Angell, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
Three-dimensional (3D) gas clathrates are ice-like but distinguished from bulk ices by containing polyhedral nano-cages to accommodate small gas molecules. Without space filling by gas molecules, standalone 3D clathrates have not been observed to form in the laboratory, and they appear to be unstable except at negative pressure. Thus far, experimental evidence for guest‐free clathrates has only been found in germanium and silicon, although guest‐free hydrate clathrates have been found, in recent simulations, able to grow from cold stretched water, if first nucleated. Herein, we report simulation evidence of spontaneous formation of monolayer clathrate ice, with or without gas molecules, …
Tuning The Magnetic And Electronic Properties Of Bilayer Graphene Nanoribbons On Si(001) By Bias Voltage, Zhuhua Zhang, Changfeng Chen, Xiao Cheng Zeng, Wanlin Guo
Tuning The Magnetic And Electronic Properties Of Bilayer Graphene Nanoribbons On Si(001) By Bias Voltage, Zhuhua Zhang, Changfeng Chen, Xiao Cheng Zeng, Wanlin Guo
Xiao Cheng Zeng Publications
We report on a systematic study of bias-voltage-induced modulation of magnetic and electronic properties of bilayer zigzag graphene nanoribbons (Z-GNRs) on Si(001) substrate by first-principles calculations. We show that the intrinsically nonmagnetic bilayer Z-GNRs exhibit magnetic ordering on the top layer while the bottom layer serves as a nonmagnetic buffer layer when adsorbed on the substrate. Interestingly, the adsorbed bilayers display distinct ribbon-width-dependent magnetoelectric effect under bias voltages. The magnetoelectric coefficient oscillates with increasing ribbon width, which arises from an interesting interplay of the interaction of the bottom ribbon layer with the substrates and the decay length of the localized …
Observation Of Earlier Two-To-Three Dimensional Structural Transition In Gold Cluster Anions By Isoelectronic Substitution: MauN- (N=8–11; M=Ag,Cu), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang
Observation Of Earlier Two-To-Three Dimensional Structural Transition In Gold Cluster Anions By Isoelectronic Substitution: MauN- (N=8–11; M=Ag,Cu), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang
Xiao Cheng Zeng Publications
The effects of isoelectronic substitution on the electronic and structural properties of gold clusters are investigated in the critical size range of the two-dimensional (2D)-three-dimensional (3D) structural transition (MAun −, n=8–11; M=Ag,Cu) using photoelectron spectroscopy and density functional calculations. Photoelectron spectra of MAun − are found to be similar to those of the bare gold clusters Aun+1 − , indicating that substitution of a Au atom by a Ag or Cu atom does not significantly alter the geometric and electronic structures of the clusters. The only exception occurs at n …
Isomer Identification And Resolution In Small Gold Clusters, Wei Huang, Rhitankar Pal, Lei-Ming Wang, Xiao Cheng Zeng, Lai-Sheng Wang
Isomer Identification And Resolution In Small Gold Clusters, Wei Huang, Rhitankar Pal, Lei-Ming Wang, Xiao Cheng Zeng, Lai-Sheng Wang
Xiao Cheng Zeng Publications
A variety of experimental techniques are used to resolve energetically close isomers of Au7 − and Au8 − by combining photoelectron spectroscopy and ab initio calculations. Two structurally distinct isomers are confirmed to exist in the cluster beam for both clusters. Populations of the different isomers in the cluster beam are tuned using Ar-tagging, O2-titration, and isoelectronic atom substitution by Cu and Ag. A new isomer structure is found for Au7 −, which consists of a triangular Au6 unit with a dangling Au atom. Isomer-specific photoelectron spectra of Au8 − are obtained …
Two-Dimensional To Three-Dimensional Structural Transition Of Gold Cluster Au 10 During Soft Landing On Tio 2 Surface And Its Effect On Co Oxidation, Hui Li, Yong Pei, Xiao Cheng Zeng
Two-Dimensional To Three-Dimensional Structural Transition Of Gold Cluster Au 10 During Soft Landing On Tio 2 Surface And Its Effect On Co Oxidation, Hui Li, Yong Pei, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
We investigate the possible structural transition of a planar Au10 cluster during its soft landing on a TiO2 (110) surface with or with no oxygen defects. The collision between the gold cluster and the oxide surface is simulated using the Car–Parrinello quantum molecular dynamics method. Both high-speed and low-speed conditions typically implemented in soft-landing experiments are simulated. It is found that under a high-speed condition, the gold cluster Au10 can undergo a sequence of structural transitions after colliding with a defect-free TiO2 (110) surface. When the TiO2 (110) surface possesses oxygen vacancies, however, chemical bonds …
Icosahedral B12-Containing Core–Shell Structures Of B80, Hui Li, Nan Shao, Bo Shang, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng
Icosahedral B12-Containing Core–Shell Structures Of B80, Hui Li, Nan Shao, Bo Shang, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
Low-lying icosahedral (Ih) B12-containing structures of B80 are explored, and a number of core–shell isomers are found to have lower energy than the previous predicted B80 fullerene. The structural transformation of boron clusters from tubular structure to core–shell structure may occur at a critical size less than B80.
Graphene-Like Bilayer Hexagonal Silicon Polymorph, Jaeil Bai, Hideki Tanaka, Xiao Cheng Zeng
Graphene-Like Bilayer Hexagonal Silicon Polymorph, Jaeil Bai, Hideki Tanaka, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
We present molecular dynamics simulation evidence for a freezing transition from liquid silicon to quasi-twodimensional (quasi-2D) bilayer silicon in a slit nanopore. This new quasi-2D polymorph of silicon exhibits a bilayer hexagonal structure in which the covalent coordination number of every silicon atom is four. Quantum molecular dynamics simulations show that the stand-alone bilayer silicon (without the confinement) is still stable at 400 K. Electronic band-structure calculations suggest that the bilayer hexagonal silicon is a quasi-2D semimetal, similar to a graphene monolayer, but with an indirect zero band gap.