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Makoto Kasu - One of the best experts on this subject based on the ideXlab platform.

  • origin of exciton emissions from an aln p n junction light emitting diode
    Applied Physics Letters, 2011
    Co-Authors: Yoshitaka Taniyasu, Makoto Kasu
    Abstract:

    Exciton emissions from an AlN light-emitting diode with an improved emission efficiency of 1×10−4% were observed at 5.94 eV (208.7 nm) and 6.10 eV (203.2 nm) by current injection. The emission at 5.94 eV is attributed to an exciton emission originating from the Crystal-Field split off valence band (CH-exciton emission). Due to the large carrier-phonon interaction, the CH-exciton emission accompanies its phonon replicas. The emission at 6.10 eV is attributed to another exciton emission originating from heavy/light hole valence bands (HH/LH-exciton emission). From the emission energies, considering residual strain, the Crystal-Field Splitting energy was determined to be −165 meV.

  • surface 210 nm light emission from an aln p n junction light emitting diode enhanced by a plane growth orientation
    Applied Physics Letters, 2010
    Co-Authors: Yoshitaka Taniyasu, Makoto Kasu
    Abstract:

    (112¯0) A-plane AlN p–n junction light-emitting diode (LED) with a wavelength of 210 nm is demonstrated. The electroluminescence from the A-plane LED is inherently polarized for the electric Field parallel to the [0001] c-axis due to a negative Crystal-Field Splitting energy. The polarization ratio (electric-Field component ratio of parallel and perpendicular to c-axis) is as high as 0.9. The radiation pattern of the A-plane LED shows higher emission intensity along the surface normal, while that of a conventional (0001) C-plane LED shows lower emission intensity along the surface normal. The different radiation patterns can be explained by the polarization property.

Michele Kotiuga - One of the best experts on this subject based on the ideXlab platform.

  • interfacial charge transfer mott state in iridate nickelate superlattices
    Proceedings of the National Academy of Sciences of the United States of America, 2019
    Co-Authors: Xiaoran Liu, Michele Kotiuga, Heungsik Kim, Alpha T Ndiaye, Yongseong Choi, Qinghua Zhang, Yanwei Cao, Mikhail Kareev, Fangdi Wen, Banabir Pal
    Abstract:

    We investigate [Formula: see text]/[Formula: see text] superlattices in which we observe a full electron transfer at the interface from Ir to Ni, triggering a massive structural and electronic reconstruction. Through experimental characterization and first-principles calculations, we determine that a large Crystal Field Splitting from the distorted interfacial [Formula: see text] octahedra surprisingly dominates over the spin-orbit coupling and together with the Hund's coupling results in the high-spin (S = 1) configurations on both the Ir and Ni sites. This demonstrates the power of interfacial charge transfer in coupling lattice, charge, orbital, and spin degrees of freedom, opening fresh avenues of investigation of quantum states in oxide superlattices.

  • interfacial charge transfer mott state in iridate nickelate superlattices
    Proceedings of the National Academy of Sciences of the United States of America, 2019
    Co-Authors: Michele Kotiuga, Alpha T Ndiaye, Yongseong Choi, Qinghua Zhang, Mikhail Kareev, J W Freeland, Lin Gu, D Haskel, Padraic Shafer, Elke Arenholz
    Abstract:

    We investigate S r I r O 3 / L a N i O 3 superlattices in which we observe a full electron transfer at the interface from Ir to Ni, triggering a massive structural and electronic reconstruction. Through experimental characterization and first-principles calculations, we determine that a large Crystal Field Splitting from the distorted interfacial I r O 6 octahedra surprisingly dominates over the spin–orbit coupling and together with the Hund’s coupling results in the high-spin (S = 1) configurations on both the Ir and Ni sites. This demonstrates the power of interfacial charge transfer in coupling lattice, charge, orbital, and spin degrees of freedom, opening fresh avenues of investigation of quantum states in oxide superlattices.

Volker Gottschalch - One of the best experts on this subject based on the ideXlab platform.

  • direct gap reduction and valence band Splitting of ordered indirect gap alinp2 studied by dark Field spectroscopy
    Physical Review B, 1996
    Co-Authors: Mathias Schubert, B Rheinlander, Ines Pietzonka, Jaroslava Skriniarova, E. Franke, Volker Gottschalch
    Abstract:

    The order-dependent valence-band Splitting and direct-gap reduction in spontaneously ordered indirect-gap AlIn${\mathrm{P}}_{2}$ are determined by dark-Field spectroscopy at room temperature. Similar to direct-gap GaIn${\mathrm{P}}_{2}$ both parameters depend on the degree of long-range $\mathrm{Cu}{\mathrm{Pt}}_{B}$-type order. We obtain the direct gap for disordered and the order-induced changes of the spin-orbit Splitting and the Crystal-Field Splitting normalized to the direct-gap change for perfectly ordered AlIn${\mathrm{P}}_{2}$.

Qinghua Zhang - One of the best experts on this subject based on the ideXlab platform.

  • dual defects adjusted Crystal Field Splitting of laco1 xnixo3 δ hollow multishelled structures for efficient oxygen evolution
    Angewandte Chemie, 2020
    Co-Authors: Qinghua Zhang, Huan Wang, Nailiang Yang, Wei Cui, Jiangyan Wang, Keke Huang, Shuyan Song, Shouhua Feng, Dan Wang
    Abstract:

    To boost the performance for various applications, a rational bottom-up design on materials is necessary. The defect engineering on nanoparticle at the atomic level can efficiently tune the electronic behavior, which offers great opportunities in enhancing the catalytic performance. In this paper, we optimized the surface oxygen vacancy concentration and created the lattice distortion in rare-earth-based perovskite oxide through gradient replacement of the B site with valence alternated element. The dual defects make the electron spin state transit from low spin state to high spin state, thus decreasing the charge transport resistance. Furthermore, assembly the modified nanoparticle subunits into the micro-sized hollow multishelled structures can provide porous shells, abundant interior space and effective contact, which enables an enhanced mass transfer and a shorter charge transport path. As a result, the systemic design in the electronic and nano-micro structures for catalyst has brought an excellent oxygen evolution performance.

  • interfacial charge transfer mott state in iridate nickelate superlattices
    Proceedings of the National Academy of Sciences of the United States of America, 2019
    Co-Authors: Xiaoran Liu, Michele Kotiuga, Heungsik Kim, Alpha T Ndiaye, Yongseong Choi, Qinghua Zhang, Yanwei Cao, Mikhail Kareev, Fangdi Wen, Banabir Pal
    Abstract:

    We investigate [Formula: see text]/[Formula: see text] superlattices in which we observe a full electron transfer at the interface from Ir to Ni, triggering a massive structural and electronic reconstruction. Through experimental characterization and first-principles calculations, we determine that a large Crystal Field Splitting from the distorted interfacial [Formula: see text] octahedra surprisingly dominates over the spin-orbit coupling and together with the Hund's coupling results in the high-spin (S = 1) configurations on both the Ir and Ni sites. This demonstrates the power of interfacial charge transfer in coupling lattice, charge, orbital, and spin degrees of freedom, opening fresh avenues of investigation of quantum states in oxide superlattices.

  • interfacial charge transfer mott state in iridate nickelate superlattices
    Proceedings of the National Academy of Sciences of the United States of America, 2019
    Co-Authors: Michele Kotiuga, Alpha T Ndiaye, Yongseong Choi, Qinghua Zhang, Mikhail Kareev, J W Freeland, Lin Gu, D Haskel, Padraic Shafer, Elke Arenholz
    Abstract:

    We investigate S r I r O 3 / L a N i O 3 superlattices in which we observe a full electron transfer at the interface from Ir to Ni, triggering a massive structural and electronic reconstruction. Through experimental characterization and first-principles calculations, we determine that a large Crystal Field Splitting from the distorted interfacial I r O 6 octahedra surprisingly dominates over the spin–orbit coupling and together with the Hund’s coupling results in the high-spin (S = 1) configurations on both the Ir and Ni sites. This demonstrates the power of interfacial charge transfer in coupling lattice, charge, orbital, and spin degrees of freedom, opening fresh avenues of investigation of quantum states in oxide superlattices.

Elke Arenholz - One of the best experts on this subject based on the ideXlab platform.

  • interfacial charge transfer mott state in iridate nickelate superlattices
    Proceedings of the National Academy of Sciences of the United States of America, 2019
    Co-Authors: Michele Kotiuga, Alpha T Ndiaye, Yongseong Choi, Qinghua Zhang, Mikhail Kareev, J W Freeland, Lin Gu, D Haskel, Padraic Shafer, Elke Arenholz
    Abstract:

    We investigate S r I r O 3 / L a N i O 3 superlattices in which we observe a full electron transfer at the interface from Ir to Ni, triggering a massive structural and electronic reconstruction. Through experimental characterization and first-principles calculations, we determine that a large Crystal Field Splitting from the distorted interfacial I r O 6 octahedra surprisingly dominates over the spin–orbit coupling and together with the Hund’s coupling results in the high-spin (S = 1) configurations on both the Ir and Ni sites. This demonstrates the power of interfacial charge transfer in coupling lattice, charge, orbital, and spin degrees of freedom, opening fresh avenues of investigation of quantum states in oxide superlattices.