Publications by authors named "Naizhang Sun"

Due to the atomic asymmetry, Janus transition metal dichalcogenide monolayers possess spontaneous curling and can even form one-dimensional nanoscrolls. Unveiling this spontaneous formation mechanism of nanoscrolls is of great importance for precise structural control. In this paper, we successfully simulate the process of Janus MoSSe nanoscroll formation from flat nanoribbons, based on molecular dynamics (MD) simulations with hybrid potentials.

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The unique physical properties exhibited by one-dimensional nanoscrolls assembled from nanosheets have propelled them into the spotlight of two-dimensional materials research. However, the self-scrolling mechanism of transition metal dichalcogenides has not been unveiled with an appropriate theoretical approach. In this paper, we systematically investigate the spontaneous formation of MoS nanoscrolls from flat monolayers by molecular dynamics simulations based on a reactive force field.

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Due to the unique optical responses induced by vertical atomic asymmetry inside a monolayer, two-dimensional Janus structures have been conceived as promising building blocks for nanoscale optical devices. In this paper, second harmonic generation (SHG) in Janus transition metal chalcogenide oxide monolayers is systematically investigated by the first-principles calculations. Second-order nonlinear susceptibilities are theoretically determined for Janus MXO (M = Mo/W, X = S/Se/Te) monolayers.

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A core-shell nanowire heterostructure is an important building block for nanowire-based optoelectronic devices. In this paper, the shape and composition evolution induced by adatom diffusion is investigated by constructing a growth model for alloy core-shell nanowire heterostructures, taking diffusion, adsorption, desorption and incorporation of adatoms into consideration. With moving boundaries accounting for sidewall growth, the transient diffusion equations are numerically solved by the finite element method.

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Based on density functional theory, we theoretically investigate the electronic structures of free-standing armchair Janus MoSSe nanoribbons (A-MoSSeNR) with width up to 25.5 nm. The equilibrium structures of nanoribbons with spontaneous curling are obtained by energy minimization in molecular dynamics (MD).

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