Dalai, M. K. and Sekhar, B. R. and Biswas, D. and Thakur, S. and Chiang, T. C. and Samal, D. and Martin, C. and Maiti, K.
(2014)
Valence-band study of Sm0.1Ca0.9-xSrxMnO3 using high-resolution ultraviolet photoelectron spectroscopy.
Physical Review B , 89 (24).
ISSN 1098-0121
Abstract
We have studied the concentration-dependent near-Fermi-level valence-band electronic structure of Sm0.1Ca0.9-xSrxMnO3 (x = 0, 0.1, 0.3, and 0.6) using high-resolution ultraviolet photoelectron spectroscopy (HRUPS) across the metal insulator transition. At low temperatures (50 and 100 K), a transformation from pseudogap type behavior (x = 0 and 0.1) to insulating behavior (x = 0.3 and 0.6) is observed with an increase in Sr content. While at the high temperatures, the metalliclike density of states appears up to x = 0.3 and then vanishes at x = 0.6. The temperature-dependent spectra reveal a changeover from pseudogap to metalliclike states for x = 0 above its magnetic cluster-glass ordering temperature (110 K). In the case of x = 0.1, the temperature-dependent change in the density of states is quite different from that of x = 0 due to the weaker cluster-glass component and exhibits an interesting spectral weight transfer in the high-temperature paramagnetic phase. These findings would immensely help in understanding the puzzling charge transport scenario in Sm0.1Ca0.9-xSrxMnO3 from a microscopic point of view.
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