2007/07/02 by K. Ebata, M. Hashimoto, Makoto Hashimoto +5
Chemistry · Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Analytical Chemistry (journal) #Atomic physics #Charge (physics) #Chemistry #Condensed matter physics #Cuprate #Doping #Electron #Fermi level #Intensity (physics) #Magnetic and transport properties of perovskites and related materials #Materials science #Multiferroics and related materials #Optics #Paramagnetism #Phase (matter) #Physics #Pseudogap #Quantum mechanics #Spectral line #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.76.174418
published as Phys. Rev. B 76, 174418 (2007) · 5pages, 7figures
arxiv created 2007/07/02 · openalex publication_date 2007/11/09 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have studied the temperature dependence of the photoemission spectra of Pr_1\ensuremath-xCaxMnO3 (PCMO) with x=0.25, 0.3, and 0.5. For x=0.3 and 0.5, we observed a gap in the low-temperature charge-exchange-type charge-ordered (CO) phase and a pseudogap with a finite intensity at the Fermi level (EF) in the high-temperature paramagnetic insulating (PI) phase. Within the CO phase, the spectral intensity near EF gradually increased with temperature. These observations are consistent with the results of Monte Carlo simulations on a model including charge ordering and ferromagnetic fluctuations [H. Aliaga et al., Phys. Rev. B 68, 104405 (2003)]. For x=0.25, on the other hand, little temperature dependence was observed within the low-temperature ferromagnetic insulating (FI) phase and the intensity at EF remained low in the high-temperature PI phase. We attribute the difference in the temperature dependence near EF between the CO and FI phases to the different correlation lengths of orbital order between both phases. Furthermore, we observed a chemical potential shift with temperature due to the opening of the gap in the FI and CO phases. The doping dependent chemical potential shift was recovered at low temperatures, corresponding to the disappearance of the doping dependent change of the modulation wave vector. Spectral weight transfer with hole concentration was clearly observed at high temperatures but was suppressed at low temperatures. We attribute this observation to the fixed periodicity with hole doping in PCMO at low temperatures.