Research topic: Phase transformation and Self-organization
Please click here for publications in this area.1. Homogenous nucleation in metals
Nucleation initiated phase
transformation occur in several natural
and man made environments. It is involved in water turning
to ice in biological systems, in the solid
phase regrowth of amorphous silicon, the vapor phase
growth of semiconductor nanowires, and in templated
growth of functional materials Therefore,
understanding this process in quantitative detail is of
broad fundamental and applied interest.
We have recently shown that classical nucleation theory can be applied to accurately predict the maximum undercooling in elemental metallic liquids. In this work, reported in the J. Appl. Phys., the free energy change involved in the liquid to solid phase change accounted for contributions from the difference in the densities of the liquid and solid phase. The result was an accurate prediction of the experimentally measured maximum undercooling in metals, first investigated extensively by David Turnbull in th 1950's. This work can be downloaded for free from the J. Appl. Phy.
We have recently shown that classical nucleation theory can be applied to accurately predict the maximum undercooling in elemental metallic liquids. In this work, reported in the J. Appl. Phys., the free energy change involved in the liquid to solid phase change accounted for contributions from the difference in the densities of the liquid and solid phase. The result was an accurate prediction of the experimentally measured maximum undercooling in metals, first investigated extensively by David Turnbull in th 1950's. This work can be downloaded for free from the J. Appl. Phy.
2. Pattern formation via Self-organization
Formation of spatially ordered patterns via self-organization is a potentially cost-effective and robust route to manufacture functional nanostructures.
In a recent Phys. Rev. Lett. paper we have reported the discovery of a novel self-organizing mechanism resulting during ns laser melting of ultrathin metal films. In this work, nanoscale thickness-dependent optical absorption of the ultraviolet laser light in the metal film in conjunction with the rapid thermal transport into the underlying substrate results in unique thickness-dependent thermocapillary forces. This results in a self-oprganizing behavior quite different from classical spinodal-like dewetting. (Link to journal article)
Publications in Phase transformation and Self-organization
- R. Kalyanaraman, Nucleation energetics during homogeneous solidification in elemental metallic liquids, J. Appl. Phys. 108, 033506 (2008). Free download from AIP.
- J.
Trice, C. Favazza, D. Thomas, R. Kalyanaraman, R. Sureshkumar, Novel
self-organization mechanisms in ultrathin liquid films: theory and
experiment, Phys. Rev. Lett. 101, 017802 (2008).
- C. Favazza, J. Trice, R. Kalyanaraman, R. Sureshkumar, Self-organized metal nanostructures through laser-interference driven thermocapillary convection, Appl. Phys. Lett. 91, 043105 (2007). (Editor selected for publication in the August 6, 2007 issue of Virtual Journal of Nanoscale Science & Technology, AIP publications)
- J. Trice, D. Thomas, C. Favazza, R. Sureshkumar, and R. Kalyanaraman, Investigation of pulsed laser induced dewetting in nanoscopic metal films: Theory and experiments, PRB, 75, 235439 (2007).
- C. Favazza, J. Trice, H. Krishna, R. Kalyanaraman, and R. Sureshkumar, Laser-induced short- and long-range orderings of Co nanoparticles on SiO2 , Appl. Phys. Lett. 88, 153118-1-3 (2006).
- C. Favazza, R. Kalyanaraman and R. Sureshkumar, Robust nanopatterning by laser-induced dewetting of metal nanofilms, Nanotechnology 17, 4229-4234 (2006).
- C.Favazza, J.Trice, A.K.Gangopadhyay, H.Garcia, R.Sureshkumar, and R. Kalyanaraman, Nanoparticle ordering by dewetting of Co on SiO2 , J. Elec. Mat. 35, 1618-1620, (2006).