Yan-Mei Yu


Institute of Physics, Chinese Academy of Science,

P. O. Box 603, Beijing 100080, China

Tel.: +86-10-82648059, Fax: +86-10-62553698,

Email: ymyu@aphy.iphy.ac.cn

EDUCATION

June 2002 Ph. D., Materials Processing Engineering, in State Key Lab of Solidification Processing, Northwestern Polytechnical University, XiĄŻan, China
Thesis: Phase-field simulation of dendrite growth in undercooled melt

March 1999 M. S., Materials Science, in State Key Lab of Solidification Processing, Northwestern Polytechnical University, XiĄŻan, China

June 1996 Bsc., Mechanical Engineering, XiĄŻan Highway Transportation University, XiĄŻan, China

EXPERIENCE

09/2002-presentAssociate Researcher (06/2005-present), Assistant Researcher (06/2004- 06/2005), Postdoctoral Fellow (09/2002-06/2004),

Lab of Condensed Matter Theory and Materials Computation, Institute of Physics, Chinese Academy of Science

HONORS

Ribbon Award Winner: MRS 2004 Fall Meeting, Symposium JJ: Modeling of Morphological Evolution at Surfaces and Interfaces, Paper TitleŁşPhase-field model for epitaxial growth of islands and nanostripes, JJ3.14

RESEARCH INTERESTS

Modeling and simulation of formation of nanostructures and evolution at surfaces and in bulk materials       

CONFERRENCE PAPERS AND PRESENTATIONS

  • Yan-Mei Yu and Bang-Gui Liu: Phase-field model for epitaxial growth of islands and nanostripes, in Modeling of Morphological Evolution at Surfaces and Interfaces, edited by J. Evans, C. Orme, M. Asta, and Z. Zhang (MRS Proc. 859E, Warrendale, PA, 2005), JJ3.14.
  • 2005 APS March Meeting, Session V40: Focus Session: Morphology and Evolution at Surfaces: Phase-field and Ge/Si, Phase Field Model for Growth of Adatom Islands, Los Angeles, CA, March 2005.
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    SELECTED PUBLICATIONS

    1. Coexistence of meandering and bunching of steps on vicinal surfaces

    Yan-Mei Yu and Bang-Gui Liu

    Institute of Physics,Center of Condensed Matter Physics, Chinese Academy of Science, P. O. Box 603, 100080, Beijing, P. R. China

    We simulate morphology and its evolution of vicinal surfaces in epitaxy by using the phase-field model. For usual parameters of Cu vicinal surfaces, a pure in-phase meandering pattern consistent to the experimental mages is obtained. Nevertheless, vicinal surfaces grow into more complex hierarchy for a small kink energy. In addition to step meandering, step bunching happens due to competition of local step fluctuation and interlayer Ehrlich-Schwoebel barrier in the presence of the step meandering. This implies that step meandering and step bunching can coexist in some growing epitaxial vicinal surfaces.Phys. Rev. B 73, 035416 (2006)
    2. Self-organized formation of regular nanostripes on vicinal surfaces

    Yan-Mei Yu and Bang-Gui Liu

    Institute of Physics,Center of Condensed Matter Physics, Chinese Academy of Science, P. O. Box 603, 100080, Beijing, P. R. China

    We explore the mechanism of self-organized formation of regular arrays of nanostripes on vicinal surfaces by using a phase-field model. Epitaxial growth during deposition usually results in both nanostripes and islands on terraces of a vicinal substrate. Post-deposition annealing at elevated temperatures induces growth of the nanostripes but makes the islands shrink. It is a ripening process of the mixed system of the nanostripes and the islands, being dependent upon the temperature and strain. It is accompanied by a transition from the diffusion-limited regime to the detachment-limited regime induced by the strain at high temperatures. This ripening makes the islands diminish and on the other hand makes the nanostripes smoother. As a result, the islands disappear completely and the regular arrays of nanostripes are formed on the vicinal substrate. This theory can explain the self-organized formation of nanostripes and nanowires on vicinal surfaces, such as the intriguing regular arrays of Fe nanostripes on the vicinal W surfaces. Phys. Rev. B 70, 051444 (2004)

    3. A phase-field model of island growth in epitaxy

    Yan-Mei Yu and Bang-Gui Liu

    Institute of Physics,Center of Condensed Matter Physics, Chinese Academy of Science, P. O. Box 603, 100080, Beijing, P. R. China

    Nucleation and growth of islands in epitaxy is simulated using a continuum phase-field model which is based on motion of island boundaries. An phase-field order parameter is introduced to distinguish the substrate and different epitaxial layers so that the motion of island boundaries is described by evolution of the phase-field. The phase field is determined by a time-dependent Ginzburg-Landau-like equation coupled to diffusive transport equation of adatoms. We first use the model to simulate the nucleation and growth of islands in submonolayer regime, reproducing the scaling property of the island density as a function of the ratio of diffusion to deposition rate. Then, we extend the phase-field simulation to the multilayer regime, reproducing mound structures of metal(100) systems. Coarsening and roughening of the mounds are investigated in this model. The simulated results validate the model. Compared with atomic models and mean-field models, this model can cover a large length and time scale of practical engineering interests, and at the same time provide a fine visualized morphology of islands. Phys. Rev. E 69, 021601 (2004)

    4. Influence of isothermal approximation on phase field simulation of directional growth in undercooled melt

    Yan-Mei Yu, Yang Gen-Cang, Zhao Da-Wen, and Lu Yi-Li

    State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an, 710072, China

    Using the phase-field approach, the directional growth of alloy in the undercooled melt is simulated on the isothermal and non-isothermal condition respectively. The influences of the isothermal approximation on simulation results are discussed. It is shown that: for the undercoolings higher than 25K, the isothermal approximation overestimates the interface growth velocity, and deduces the critical velocity for an absolute stable planar interface, therefore in the isothermal simulation, the interface morphology occurs the plane-cell-plane transition with the increasing initial undercoolings of the melt and the planar interface obtained under the large undercooling is absolute stable, whereas in the non-isothermal simulation, only plane-cell transition happens in the same range of the initial undercoolings of the melt, and the planar interface trends to destabilize and gives cells. Chinese Physics. 12, 211(2003)

    5. Yan-Mei Yu, GC Yang, DW Zhao, and YL Lu, Effects of temperature boundary conditions on dendritic growth in phase-field simulations of binary alloy. The Chinese Journal of Nonferrous Metals, 12, 1063 (2002).

    6. Yan-Mei Yu and Hua-Lun Li, A new method for fabrication of Cu-Al2O3 Composite by Internal Oxidation, Powder Metallurgy Technology 18, 525 (2000) EIP01035572809, in Chinese.

    7. Yan-Mei Yu and Hua-Lun Li, Reaction Kinetics of Internal Oxidation Fabrication of Al2O3-Cu, J. Northwestern Polytechnical University 18, 661 (2000), in Chinese.
     
    last update:21/03/2006