Electronic correlations in FeGa$_3$ and the effect of hole doping on its magnetic properties
Physical Review B, Vol 89, p. 195102 (2014) We investigate signatures of electronic correlations in the narrow-gap semiconductor FeGa$_3$ by means of electrical resistivity and thermodynamic measurements performed on single crystals of FeGa$_3$, Fe$_{1-x}$Mn$_x$Ga$_3$ and FeGa$_{3-y}$Zn$_y$, complem...
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Main Authors | , , , , , |
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Format | Journal Article |
Language | English |
Published |
09.05.2014
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Subjects | |
Online Access | Get full text |
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Summary: | Physical Review B, Vol 89, p. 195102 (2014) We investigate signatures of electronic correlations in the narrow-gap
semiconductor FeGa$_3$ by means of electrical resistivity and thermodynamic
measurements performed on single crystals of FeGa$_3$, Fe$_{1-x}$Mn$_x$Ga$_3$
and FeGa$_{3-y}$Zn$_y$, complemented by a study of the 4$d$ analog material
RuGa$_3$. We find that the inclusion of sizable amounts of Mn and Zn dopants
into FeGa$_3$ does not induce an insulator-to-metal transition. Our study
indicates that both substitution of Zn onto the Ga site and replacement of Fe
by Mn introduces states into the semiconducting gap that remain localized even
at highest doping levels. Most importantly, using neutron powder diffraction
measurements, we establish that FeGa$_3$ orders magnetically above room
temperature in a complex structure, which is almost unaffected by the doping
with Mn and Zn. Using realistic many-body calculations within the framework of
dynamical mean field theory (DMFT), we argue that while the iron atoms in
FeGa$_3$ are dominantly in an $S=1$ state, there are strong charge and spin
fluctuations on short time scales, which are independent of temperature.
Further, the low magnitude of local contributions to the spin susceptibility
advocates an itinerant mechanism for the spin response in FeGa$_3$. Our joint
experimental and theoretical investigations classify FeGa$_3$ as a correlated
band insulator with only small dynamical correlation effects, in which
non--local exchange interactions are responsible for the spin gap of 0.4 eV and
the antiferromagnetic order. We show that hole doping of FeGa$_3$ leads, within
DMFT, to a notable strengthening of many--body renormalizations. |
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DOI: | 10.48550/arxiv.1405.2369 |