arXiv subjects

Hong Guo

Publications and source records attributed to Hong Guo.

381 records · Page 22Linked to original sources

arXiv1996

Numerical confirmation of universality of transmission micro-symmetry relations in a four-probe quantum dot

We study the crossover behavior of the Hall resistance between the integer quantum Hall regime and a regime dominated by the Aharonov-Bohm oscillations, in a system of 4-probe quantum dot with an artificial impurity confined inside. In a previous study [M. Lei, N.J. Zhu and Hong Guo, Phys. Rev. B. 52, 16784, (1995)], a peculiar set of symmetry relations between various scattering probabilities were found in this crossover regime. In this paper we examine the universality of this set of symmetry relations using different shapes of the quantum dot and positions of the artificial impurity. The symmetry holds for these changes and we conclude that in this transport regime the general behavior of the Hall resistance is determined by the competition of the quantum Hall and Aharonov-Bohm effects, rather than by the detailed shapes of the structure.

cond-mat↗

arXiv1996

Frequency dependent admittance of a two-dimensional quantum wire

The frequency dependent conductance of a two-dimensional quantum wire is computed using a current conserving formalism. The correction to the dc-conductance due to a time-dependent potential is related to the local partial density of states which we compute numerically. The current conservation is explicitly confirmed by computing the global density of states and comparing it with a quantity which is related to the electron dwell time. Our calculation clearly reveals the physical meaning of the various partial density of states.

cond-mat↗

arXiv1995

Dendritic growth at very low undercoolings

We have performed numerical simulations of dendritic growth at very low undercoolings in two spatial dimension using a phase-field model. In this regime of growth, the dendrites present sharp corners in the tip region while the trailing region is parabolic, and the corresponding side-branching structures resemble the shape of the tip. The scaling $vρ^2\sim constant$, where $ρ$ is the tip radius of curvature from the fitting to the parabolic trailing region, still holds approximately. We find that the values of $vρ^2$ are consistent with those given by microscopic solvability theory. The sharpness of the tip region of the dendrite can be characterized in terms of the deviation $λ$ with respect to an Ivantsov parabola. We observe that this length scales as $λ\sim ρ$, consistent with experimental measurements.

cond-mat↗