Young Jun Chang

Critical thickness of ultrathin ferroelectric BaTiO3 films

To investigate the critical thickness of ferroelectric BaTiO3 (BTO) films, we fabricated fully strained SrRuO3∕BTO∕SrRuO3 heterostructures on SrTiO3 substrates by pulsed laser deposition with in situ reflection high-energy electron diffraction. We varied the BTO layer thickness from 3to30nm. By fabricating 10×10μm2 capacitors, we could observe polarization versus electric-field hysteresis loops, which demonstrate the existence of ferroelectricity in BTO layers thicker than 5nm. This observation provides an experimental upper bound of 5nm for the critical thickness. The BTO thickness-dependent scaling of the remanent polarization agrees with the predictions of recent first-principle simulations [J. Junquera and P. Ghosez, Nature 422, 506 (2003)].

Electronic structure of graphene on single-crystal copper substrates

The electronic structure of graphene on Cu(111) and Cu(100) single crystals is investigated using low energy electron microscopy, low energy electron diffraction and angle resolved photoemission spectroscopy. On both substrates the graphene is rotationally disordered and interactions between the graphene and substrate lead to a shift in the Dirac crossing of

Highly p-doped epitaxial graphene obtained by fluorine intercalation

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Giant Ambipolar Rashba Effect in the Semiconductor BiTeI

-0.3 eV and the opening of a

Fundamental Thickness Limit of Itinerant Ferromagnetic SrRuO3 Thin Films

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Structure and correlation effects in semiconducting SrTiO

250 meV gap. Exposure of the samples to air resulted in intercalation of oxygen under the graphene on Cu(100), which formed a (

Control of silicidation in HfO2∕Si(100) interfaces

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Kinetic roughening of ion-sputtered Pd(001) surface: beyond the Kuramoto-Sivashinsky model.

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Infrared-optical spectroscopy of transparent conducting perovskite (La,Ba)SnO3 thin films

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Selective growth of perovskite oxides on SrTiO3 (001) by control of surface reconstructions

superstructure. The effect of this intercalation on the graphene