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Junyi Zhu

Publications and source records attributed to Junyi Zhu.

60 records · Page 4Linked to original sources
arXiv2015

Dressing by regularization to the Gerdjikov-Ivanov equation and the higher-order soliton

Higher-order solitons, as well as simple $N$-soliton solutions, of the Gerdjikov-Ivanov equation are derived by the dressing method based on the technique of regularization. By the dressing transformation for the eigenfunction associated with a seed solution, the regularity conditions of the dressed eigenfunctions are found to establish the relationship between the potential and the scattering data.

nlin.SI↗
arXiv2015

Pseudo-Hydrogen Passivation_A Novel Way to Calculate Absolute Surface Energy of Zinc Blende (111) Surface

Determining accurate absolute surface energies for polar surfaces of semiconductors has been a great challenge in decades. Here, we propose pseudo-hydrogen passivation to calculate them, using density functional theory approaches. By calculating the energy contribution from pseudo-hydrogen using either a pseudo molecule method or a tetrahedral cluster method, we obtained (111) surfaces energies of Si, GaP, and ZnS with high self-consistency. This method quantitatively confirms that surface energy is determined by the number and the energy of dangling bonds of surface atoms. Our findings may greatly enhance the basic understandings of different surfaces and lead to novel strategies in the crystal growth.

cond-mat.mtrl-sci↗
arXiv2014

Cusp solitons to the long-short waves equation and the $\bar\partial$-dressing method

The dressing method based on $3\times3$ matrix $\bar{\partial}$-problem is extended to study the long-short waves equation with the cases $σ=\pm1$. The soliton solutions for the long-short wave equation for $σ=\pm1$ are given by means of the properties of Cauchy matrix. It is shown that the long-short wave equation for $σ=1$ has the cusp solitons.

math-ph↗
arXiv2014

The discrete mKdV equation revisited: a Riemann-Hilbert approach

We study the plus and minus type discrete mKdV equation. Some different symmetry conditions associated with two Lax pairs are introduced to derive the matrix Riemann-Hilbert problem with zero. By virtue of regularization of the Riemann-Hilbert problem, we obtain the complex and real solution to the plus type discrete mKdV equation respectively. Under the gauge transformation between the plus and minus type, the solutions of minus type can be obtained in terms of the given plus ones.

nlin.SI↗
arXiv2011

Quantum Stress: Density Functional Theory Formulation and Physical Manifestation

The concept of "quantum stress (QS)" is introduced and formulated within density functional theory (DFT), to elucidate extrinsic electronic effects on the stress state of solids and thin films in the absence of lattice strain. A formal expression of QS (σ^Q) is derived in relation to deformation potential of electronic states (Ξ) and variation of electron density (Δn), σ^Q = ΞΔn, as a quantum analog of classical Hook's law. Two distinct QS manifestations are demonstrated quantitatively by DFT calculations: (1) in the form of bulk stress induced by charge carriers; and (2) in the form of surface stress induced by quantum confinement. Implications of QS in some physical phenomena are discussed to underlie its importance.

cond-mat.other↗