18,722 research outputs found
Site specific spin dynamics in BaFe2As2: tuning the ground state by orbital differentiation
The role of orbital differentiation on the emergence of superconductivity in
the Fe-based superconductors remains an open question to the scientific
community. In this investigation, we employ a suitable microscopic spin probe
technique, namely Electron Spin Resonance (ESR), to investigate this issue on
selected chemically substituted BaFeAs single crystals. As the
spin-density wave (SDW) phase is suppressed, we observe a clear increase of the
Fe 3 bands anisotropy along with their localization at the FeAs plane. Such
an increase of the planar orbital content interestingly occurs independently on
the chemical substitution responsible for suppressing the SDW phase. As a
consequence, the magnetic fluctuations combined with the resultant particular
symmetry of the Fe 3 bands are propitious ingredients to the emergence of
superconductivity in this class of materials.Comment: 6 pages, 5 figure
Single-particle momentum distribution of Efimov states in noninteger dimensions
We studied the single-particle momentum distribution of mass-imbalanced
Efimov states embedded in noninteger dimensions. The contact parameters, which
can be related to the thermodynamic properties of the gas, were calculated from
the high momentum tail of the single particle densities. We studied the
dependence of the contact parameters with the progressive change of the
noninteger dimension, ranging from three (D=3) to two (D=2) dimensions. Within
this interval, we move from the (D=3) regime where the Efimov discrete scale
symmetry drives the physics, until close to the critical dimension, which
depends on the mass imbalance, where the continuum scale symmetry takes place.
We found that the two- and three-body contacts grow significantly in magnitude
with the decrease of the noninteger dimension towards the critical dimension,
impacting observables of resonantly interacting trapped Bose gases
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