SearcharxivSearch

arXiv subjects

Jian-Chun Wu

Publications and source records attributed to Jian-Chun Wu.

2 recordsLinked to original sources

Spontaneous rectification and absolute negative mobility of inertial Brownian particles induced by Gaussian potentials in steady laminar flows

We study the transport of inertial Brownian particles in steady laminar flows in the presence of two-dimensional Gaussian potentials. Through extensive numerical simulations, it is found that the transport is sensitively dependent on the external constant force and the Gaussian potential. Within tailored parameter regimes, the system exhibits a rich variety of transport behaviors. In the absence of any external driving forces, the spontaneous rectification of the particles can be manipulated by the spatial position of the Gaussian potential. Moreover, when the potential lies at the center of the cellular flow, the system exhibits absolute negative mobility (ANM), i.e., the particles can move in a direction opposite to the constant force. More importantly, the phenomenon of ANM induced by Gaussian potential is robust in a wider range of the system parameters and can be further strengthened with the optimized parameters, which may pave the way to the implementation of related experiments.

cond-mat.soft

Effects of Geometry and Symmetry on Electron Transport through Graphene-Carbon-Chain Junctions

The electron transport between two zigzag graphene nanoribbons (ZGNRs) connected by carbon atomic chains has been investigated by the nonequilibrium Green's function method combined with the density functional theory. The symmetry of the orbitals in the carbon chain selects critically the modes and energies of the transporting electrons. The electron transport near the Fermi energy can be well-manipulated by the position and the number of carbon chains contacting the nanoribbons. In symmetric ZGNRs connected by a central carbon chain, a square conductance step appears at the Fermi energy because the antisymmetric modes below it are not allowed to go through the chain. These modes can additionally contribute to the conductance if side carbon chains are added in the connection. By choosing a proper geometry configuration, we can realize Ohmic contact, current stabilizer, or the negative differential resistance phenomenon in the devices.

cond-mat.mes-hall