List of publications:
Resillient quasiparticles in a warm
Many metals in which electronic correlations are important are
, that is, resisistivity in them exceeds the Mott-Ioffe-Regel
value which corresponds to the resistivity a material has when the
scattering events are so frequent that the electron mean-free path is
equivalent to the lattice spacing. In a paper we explored the
temperature evolution of resistivity and the relation of resistivity
to the spectral properties in a simple model DMFT setting. On the
technical side, in this paper we found an excellent agreement between
the real-frequency numerical renormalization group solver and the
quantum Monte-Carlo hybridization expansion results.
Electronic correlations in
Strong correlations from Hund's
Published in Annual Review of Condensed Matter Physics
Many materials are multi-orbital, that is, more than one active
orbital is important. The Hund's rule coupling that splits atomic
multiplet splittings has been found to importantly affect the strength
of electronic correlations in a way that depends on the filling of the
orbitals. Hund's rule coupling can cause strong correlations far from
a Mott insulating state. Materials in which Hund's rule coupling is
playing the key role are known as Hund's metals. Ruthenates and iron
pnictides are important members of that family of compounds.
Spin-thermoelectric effect in
Spin Seebeck in a quantum dot.
When time-reversal symmetry is broken the thermal gradient leads to
spin-current. In this
work we investigated this spin-thermoelectric
effect in a quantum dot described by exactly screened Anderson model.
Interesting non-Fermi liquid effects are discussed
Low energy optical conductivity
Optical conductivity of
The low frequency optical response in layered strontium ruthenate behaves in
accordance with Fermi liquid predictions. On the other hand, the
optical response of CaRuO3 decays as an anomalous power-law. In a work
we have shown that it is the low-energy interband transitions that are causing
the anomalous optical response.
Equation of state and transport in hcp-Fe under pressure
Equation of state in
hcp-Fe is a phase of iron that is stable if a pressure around 7GPa is
applied. At low temperatures it becomes superconducting. It is
believed also to be the main consitutent of the Earth-Core (where the
pressure is much larger, however, around 300GPa). hcp-Fe is not
described well by density-functional theory. In this work we have shown that good
description of hcp-Fe is obtained if correlations described by the
DMFT are included. The resistivity was, however, found to be severely
underestimated. Developing techniques that would correctly describe
the missing scattering is one of the future directions of my research.
Magnetic properties of technetium perovskites
Evolution of Neel temperature as a function of interaction strength.
Techneatates are perovksite compounds with a half-filled 4d t2g
electron shell. Recently record Neel temperature was reported in
SrTcO3. Within the LDA+DMFT approach we investigated why this is so.