Neutron Structural analysis of La_1−xSr_xMnO₃ —Variation of One-Electron Bandwidth W with Hole Doping—

抄録

We have performed neutron powder diffraction measurements for La_1−xSr_xMnO₃ (x=0.00–0.20) at room temperature. We have found that the crystal structure is orthorhombic (Pbnm, Z=4; O) at x≤0.14 and rhombohedral (R\\bar3c, Z=2; R) at x≥0.18, respectively. At this structural phase transition, the averaged Mn–O–Mn bond angle ⟨θ⟩ discontinuously increases from 160.8° at x=0.14 to 163.5° at x=0.18. We have estimated relative variation of the one-electron bandwidth W of the e_g-band, and discussed the insulator-metal behavior induced by hole doping.