Affiliation: | 1. Dipartimento di Matematica e Fisica, Università Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy;2. Nano-Bio Spectroscopy Group, Departamento de Fìsica de Materiales, Universidad del Paìs Vasco UPV/EHU, E-20018 San Sebastiàn, Spain;1. National Polytechnic Institute, ESFM, Mexico, D.F. 07738, Mexico;2. National Polytechnic Institute, UPIITA, Mexico, D.F. 07320, Mexico;1. Yerevan State University, Faculty of Physics, Department of Solid State Physics, 1 Al. Manoogian, Yerevan 0025, Armenia;2. State Engineering University of Armenia, 105, V. Teryan, Yerevan 0009, Armenia |