Size dependence of confined acoustic phonons in CuCl nanocrystals

2019-10-26 15:04:12

acoustic nanocrystals confined phonons CuCl

责任者: Jialong Zhao;Masumoto, Y. 单位: Inst. of Phys., Tsukuba Univ., Ibaraki, Japan 来源出处: Physical Review B (Condensed Matter)(Phys. Rev. B, Condens. Matter (USA)),1999/08/15,60(7):4481-4 摘要: Persistent spectral hole burning spectroscopy was used to study the size dependence of the confined acoustic phonons in CuCl nanocrystals embedded in silicate glass, NaCl, and KCl. It is found that the energies of the confined acoustic phonons in the nanocrystals in glass and KCl are almost the same, but twice larger than those in NaCl, which were obtained from the Stokes-side acoustic phonon holes with the same excitation energies. The confined acoustic phonons in the nanocrystals in glass and KCl can be well explained in terms of the lowest-frequency vibrational modes calculated on a sphere model with a free boundary condition. However, the energies of the confined acoustic phonons in the nanocrystals in NaCl are lower than the frequencies of the lowest-frequency vibrational modes predicted by a cube model with a free boundary condition. This observation shows that the energies of the confined acoustic phonons in CuCl nanocrystals depend on the size, the shape, and the boundary condition of the nanocrystals 关键词: copper compounds;nanostructured materials;optical hole burning;phonon spectra;semiconductor doped glasses;semiconductor materials;size dependence;confined acoustic phonons;CuCl nanocrystals;persistent spectral hole burning spectroscopy;silicate glass;NaCl;KCl;acoustic phonons;Stokes-side acoustic phonon holes;lowest-frequency vibrational modes;free boundary condition;sphere model;cube model;nanocrystals;SiO2:CuCl;NaCl:CuCl;KCl:CuCl