Yusupov, R. V.; Conder, K.; Mertelj, T.; Mihailovic, D.; … - In: The European Physical Journal B - Condensed Matter and … 54 (2006) 4, pp. 465-469
The infrared photo-induced spectra of the isotope-substituted stoichiometric La<Subscript>2</Subscript>CuO<Subscript>4</Subscript> samples were studied at T=20 K. Measured spectra were analyzed within the small polaron hopping theory. A small, but detectable shift of the effective phonon frequency on the substitution <Superscript>16</Superscript>O to <Superscript>18</Superscript>O is found...</superscript></superscript></subscript></subscript>