Takashi Miyake

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We have investigated by first principles the electronic, vibrational, and structural properties of bct C4, a new form of crystalline sp{3} carbon recently found in molecular dynamics simulations of carbon nanotubes under pressure. This phase is transparent, dynamically stable at zero pressure, and more stable than graphite beyond 18.6 GPa. Coexistence of(More)
We investigate the effect of electronic correlations onto the thermoelectricity of semiconductors and insu-lators. Appealing to model considerations, we study various many-body renormalizations that enter the ther-moelectric response. We find that, contrary to the case of correlated metals, correlation effects do not per se enhance the Seebeck coefficient(More)
Solid hydrogen, an important constituent of some planets, has been attracting not only geophysicists but also physicists working on condensed matter physics for more than six decades. Recent high-pressure studies revealed three relevant phases of solid molecular hydrogen: phase I (high-temperature, low-pressure phase), phase II (low-temperature phase), and(More)
In nodal-line semimetals, the gaps close along loops in k space, which are not at high-symmetry points. Typical mechanisms for the emergence of nodal lines involve mirror symmetry and the π Berry phase. Here we show via ab initio calculations that fcc calcium (Ca), strontium (Sr) and ytterbium (Yb) have topological nodal lines with the π Berry phase near(More)
We calculate the electronic structure of Sr(2)RuO(4), treating correlations within dynamical mean-field theory. The approach successfully reproduces several experimental results and explains the key properties of this material: the anisotropic mass renormalization of quasiparticles and the crossover into an incoherent regime above a low temperature scale.(More)
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