Past projects:

Charge fluctuations in Yb f-shell |
Fluctuating
vs
intermediate valence - valence transition in Yb under pressure The 4f shell of Yb can
accomodate 13 or 14 electrons depending on a particular compound. This
near degenracy of f
^{13} and
f^{14 }valence
states has deep consequences. Using LDA+DMFT we instigate continuous
transition between the f^{13}
and f^{14 }valence
states
in elemental Yb induced by pressure and discuss it in terms of fluctuating and intermediate valence concepts.Fluctuating valence and valence transition in Yb (presentation pdf) |

Pyrite crystal structure of NiS _{2} |
Metal-insulator
transition
in NiS_{2-x}Se_{x
} _{The
NiS2-xSex solid solution provides a model system where the trantion
between metallic phase and the Mott insulator can be tuned by Se
content, pressure or temperature. Using LDA+DMFT we show that, contrary
to common claims, the transition is essentially controlled by varying
hybridization gap within the S(Se) p-band related to the bond length
of the S-S (Se-Se) dimer.
}Is NiS_{2} a charge-transfer insulator?
(presentation pdf) |

Nesting function of compressed fcc Li |
Superconductivity
of
compressed fcc Li Discovery of higher temperature
superconductivity in MgB
_{2} brought about a renewed
interest in strongly coupled conventional superconductors.
Surprizingly Li, one of the simplest possible solids,
turns out to be ~20 K superconductor when compressed. We
use density functional electronic structure and linear response
theory to investigate the origin of Li superconductivity and lattice
dynamics and to link the effects to the Fermi surface topology.Superconductivity and lattice instability of Li under pressure (presentation pdf) |

Change of inter-band conductivity below T _{c} |
Electronic
structure
of EuB_{6}Presence of a gap in the bandstructure of EuB _{6} has been
controversial for some time. We have studied the spectral weight
transfer in the optical spectrum induced by magnetic ordering and
conclude that the observed behavior is consistent only with a
semimetallic groundstate.Electronic structure of EuB6: insights from optical spectroscopy (presentation pdf) |