In: Physical Review Letters, 2010, vol. 104, no. 3, p. 036401
We report spectroscopic ellipsometry measurements of the anisotropy of the interband transitions parallel and perpendicular to the planes of (LaTiO₃)n(LaAlO₃)5 multilayers with n=1–3. These provide direct information about the electronic structure of the two-dimensional (2D) 3d¹ state of the Ti ions. In combination with local density approximation, including a Hubbard U calculation, we...
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In: Physical Review Letters, 2008, vol. 101, no. 17, p. 177404
We investigated temperature dependent optical spectra of the one-dimensional chain compound Sr₂CuO₃. The charge transfer transition polarized along the chain direction shows a strongly asymmetric line shape as expected in one-dimensional extended Hubbard model. At low temperature, the charge transfer peak shows a large blueshift and reveals additional sharp peaks at the gap. Even though many...
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In: Physical Review Letters, 2008, vol. 101, no. 22, p. 226402
We investigated the electronic structures of the 5d Ruddlesden-Popper series Sr₊₁IrnO₃₊₁ (n=1, 2, and ∞) using optical spectroscopy and first-principles calculations. As 5d orbitals are spatially more extended than 3d or 4d orbitals, it has been widely accepted that correlation effects are minimal in 5d compounds. However, we...
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In: Physical Review Letters, 2007, vol. 99, no. 26, p. 266801
We used infrared spectroscopic ellipsometry to investigate the electronic properties of LaTiO₃/SrTiO₃ superlattices (SLs). Our results indicated that, independent of the SL periodicity and individual layer thickness, the SLs exhibited a Drude metallic response with sheet carrier density per interface ≈3×10¹⁴ cm⁻². This is probably due to the leakage of d electrons at...
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