A new conducting salt (ET)âC(CN)â, the first 2:1 salt of ET (i.e., bis(ethylenedithio)tetrathiafu... more A new conducting salt (ET)âC(CN)â, the first 2:1 salt of ET (i.e., bis(ethylenedithio)tetrathiafulvalene) with a planar-triangular anion, was synthesized, and its structure was determined by single-crystal x-ray diffraction. Crystals data for (ET)âC(CN)â are as follows: monoclinic, P2/a, Z = 2; at 125 K/298 K, a = 14.684 (8)/14.979 (7) /angstrom/, b = 6.667 (3)/6.700 (2) /angstrom/, c = 16.400 (6)/
Journal of Molecular Structure-theochem - J MOL STRUC-THEOCHEM, 2000
Based on non-spin-polarized electronic band structure calculations, we examined why the electroni... more Based on non-spin-polarized electronic band structure calculations, we examined why the electronic structure of a semi-Heusler compound ABX has the 18-electron band gap, why 17-and 19-electron ABX compounds can be weakly ferromagnetic based on the Stoner criterion, and how the ferromagnetism of the 22-electron ABX compounds differs from that of the 17- and 19-electron analogs. To a first approximation, the electronic structure of ABX with 18 or more valence electrons is described in terms of the d10 ion for B, the s2p6 ion for X, and the dn ion for A (n=0, 1 and 4 for the case of 18, 19 and 22 valence electrons, respectively). Even for a 17-electron ABX compound the d-electron count for the electronegative transition metal B is close to d10. The ferromagnetism of the 17- and 19-electron ABX compounds is explained in terms of the Stoner criterion, and that the 22-electron ABX compounds by the strong tendency for the d-electrons of the d4 ion to localize.
Journal of Superconductivity and Novel Magnetism, 2012
On the basis of first principles density functional calculations, we investigated the effect of s... more On the basis of first principles density functional calculations, we investigated the effect of spin flip and hole doping on the spin, charge and lattice degrees of freedom in the square planar CuO2 layers of the high-T c cuprate superconductors. The local responses of the CuO2 layers to these point defects appear as spatially extended spin-charge-lattice coupled polarons in ferromagnetic clusters and hence introduce heterogeneity. The results demonstrate the need to treat the spin, charge and lattice degrees of freedom on an equal footing in describing the high-T c superconductivity.
A new conducting salt (ET)âC(CN)â, the first 2:1 salt of ET (i.e., bis(ethylenedithio)tetrathiafu... more A new conducting salt (ET)âC(CN)â, the first 2:1 salt of ET (i.e., bis(ethylenedithio)tetrathiafulvalene) with a planar-triangular anion, was synthesized, and its structure was determined by single-crystal x-ray diffraction. Crystals data for (ET)âC(CN)â are as follows: monoclinic, P2/a, Z = 2; at 125 K/298 K, a = 14.684 (8)/14.979 (7) /angstrom/, b = 6.667 (3)/6.700 (2) /angstrom/, c = 16.400 (6)/
Journal of Molecular Structure-theochem - J MOL STRUC-THEOCHEM, 2000
Based on non-spin-polarized electronic band structure calculations, we examined why the electroni... more Based on non-spin-polarized electronic band structure calculations, we examined why the electronic structure of a semi-Heusler compound ABX has the 18-electron band gap, why 17-and 19-electron ABX compounds can be weakly ferromagnetic based on the Stoner criterion, and how the ferromagnetism of the 22-electron ABX compounds differs from that of the 17- and 19-electron analogs. To a first approximation, the electronic structure of ABX with 18 or more valence electrons is described in terms of the d10 ion for B, the s2p6 ion for X, and the dn ion for A (n=0, 1 and 4 for the case of 18, 19 and 22 valence electrons, respectively). Even for a 17-electron ABX compound the d-electron count for the electronegative transition metal B is close to d10. The ferromagnetism of the 17- and 19-electron ABX compounds is explained in terms of the Stoner criterion, and that the 22-electron ABX compounds by the strong tendency for the d-electrons of the d4 ion to localize.
Journal of Superconductivity and Novel Magnetism, 2012
On the basis of first principles density functional calculations, we investigated the effect of s... more On the basis of first principles density functional calculations, we investigated the effect of spin flip and hole doping on the spin, charge and lattice degrees of freedom in the square planar CuO2 layers of the high-T c cuprate superconductors. The local responses of the CuO2 layers to these point defects appear as spatially extended spin-charge-lattice coupled polarons in ferromagnetic clusters and hence introduce heterogeneity. The results demonstrate the need to treat the spin, charge and lattice degrees of freedom on an equal footing in describing the high-T c superconductivity.
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Papers by M.-h Whangbo