Mid-infrared optical conductivity spectra of Nd1-xSrMnO3: orbital pattern dependent polaron hopping

We investigated temperature-dependent optical conductivity spectra sigma(om ega) of Nd1-xSrMnO3 (x = 0.40, 0.50, 0.54, and 0.65) single crystals. At ro om temperature, mid-infrared sigma(omega) are nearly the same for all compo sitions and spectral weights seem to depend only on the doping concentratio n. At low temperature, however, sigma(omega) are quite different and spectr al weights seem to strongly depend on the orbital/spin patterns, i.e., F (x = 0.40), CE (x = 0.50). A (x = 0.54), and C (x = 0.65)-type. We will discu ss the strong doping dependence of the mid-infrared optical conductivity sp ectra in terms of the orbital pattern dependent Jahn-Teller polaron hopping . (C) 2001 Elsevier Science B.V. All rights reserved.