resumo
In implantation experiments, the implanted particle is shot with a certain energy into the material and comes to rest at a site which may not correspond to the final position. The rearrangements of the surrounding atoms to accommodate the particle, i.e., the reaction with the host atoms may require some time and lead to delayed formation of the final states. In the case of the implantation of positive muons, this rearrangement process can be followed on a timescale of nanoseconds to microseconds. A delay is expected if an energy barrier inhibits the prompt reaction. We note that the barrier height may change during the rearrangement of the lattice, thus giving rise to a two-dimensional potential profile for the conversion process. The barrier model describes the reaction path of the muon in analogy to the passage over a mountain with a saddle point. The passing over the saddle point corresponds to the lowest energy trajectory. As an example, we discuss the application of the barrier model to solid Lu2O3.
palavras-chave
SHALLOW-DONOR; HYDROGEN; OXIDE; STATES; AL2O3
categoria
Materials Science; Physics
autores
Vilao, RC; Vieira, RBL; Alberto, HV; Gil, JM; Weidinger, A; Lichti, RL; Mengyan, PW; Baker, BB; Lord, JS
nossos autores
Ricardo Vieira
Investigador Júnioragradecimentos
The use of the ISIS and TRIUMF beams and the help of the respective muon teams are gratefully acknowledged. This work was supported with funds from (i) FEDER (Programa Operacional Factores de Competitividade COMPETE) and from FCT - Fundacao para a Ciencia e a Tecnologia under projects UID/FIS/04564/2016 and PTDC/FIS/102722/2008; (ii) Ph.D. grant SFRH/BD/87343/2012 from FCT - Fundacao para a Ciencia e a Tecnologia (RBLV). The Texas Tech group gratefully acknowledges support from the Texas Research Incentive Program.