Comparison of the temperature-dependent electronic structure of the perovskites La_0.65Ca_0.35MnO₃ (A=Ca, Ba)

Authors

D.N. McIlroy, University of Nebraska-Lincoln
C. Waldfried, University of Nebraska-Lincoln
Jiandi Zhang, University of Nebraska-LincolnFollow
Jaewu Choi, University of Nebraska-LincolnFollow
F. Foong, University of Nebraska-Lincoln
Sy_Hwang Liou, University of Nebraska-LincolnFollow
Peter A. Dowben, University of Nebraska-LincolnFollow

Date of this Version

12-15-1996

Comments

Published by American Physical Society. Copyright 1996. Permission to use. Phys. Rev. B 54 (1996) 17438-17451. http://prb.aps.org/.

Abstract

The electronic band structure and the local screening effects of the transition-metal perovskites La_0.65A_0.35MnO₃ (A=Ba and Ca ) have been examined across the coupled magnetic-metallic phase transition using the techniques of angle-resolved photoemission, resonance photoemission, and inverse photoemission. Temperature-dependent band shifts of the e_g and t_2g bands of La_0.65Ca_0.35MnO₃ have been observed. These changes in the observed electronic structure correlate with the phase transition, and are in qualitatively agreement with the predicted behavior associated with double exchange coupled with a dynamic Jahn-Teller distortion. Similar shifts were not observed for La_0.65Ba_0.35MnO₃. The changes in local screening across the Curie temperature were substantially larger for La_0.65Ca_0.35MnO₃ than for La_0.65Ba_0.35MnO3. This is consistent with the less itinerant band structure of La_0.65Ca_0.35MnO₃, as compared to the highly dispersive bands of La_0.65Ba_0.35MnO₃. These results suggest that there is less hybridization in La_0.65Ca_0.35MnO₃, as compared to La_0.65Ba_0.35MnO₃. The results point to greater electron localization in the La_0.65Ca_0.35MnO₃ compound.