2004/06/16 by E. Sondergard, O. Kerjan, C. Barreteau +1
Physics and Astronomy · #cond-mat.mtrl-sci
paper · pdf · doi:10.1016/j.susc.2004.03.072
published as Surface Science 559 (2004) 131-140
arxiv created 2004/06/16 · arxiv updated 2009/12/01
The structure of titanium films on α- Al2O3(0001) surfaces at room temperature was investigated through in situ reflection high energy electron diffraction (RHEED). The α-phase of titanium was observed to grow with the Ti(0001) || Al2O3(0001), Ti[1100] || Al2O3[2110] and Ti[1010] || Al2O3[1100] epitaxy. For up to 6 nm thick films, an other structure was found to coexist with α-Ti. Its presence has dramatic consequences for the wetting of silver, which partly explains the nontrivial buffer effect of titanium at the silver/alumina interface. From the RHEED data, the extra structure is assigned to the high-pressure hexagonal ω-Ti phase. This is supported by tight-binding total energy calculations that demonstrate that the ωphase could actually be stabilized by the α- Al2O3(0001) substrate.