Choi WS, Kim DG, Seo SSA, Moon SJ, Lee D, Lee JH, Lee HS, Cho DY, Lee YS, Murugavel P, et al. Electronic structures of hexagonal RMnO3 (R=Gd, Tb, Dy, and Ho) thin films: Optical spectroscopy and first-principles calculations. Phys. Rev. B. 2008;77:045137.
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