135 research outputs found
Inverse Proximity Effects at Spin-Triplet Superconductor-Ferromagnet Interface
We investigate inverse proximity effects in a spin-triplet superconductor
(TSC) interfaced with a ferromagnet (FM), assuming different types of magnetic
profiles and chiral or helical pairings. The region of the coexistence of
spin-triplet superconductivity and magnetism is significantly influenced by the
orientation and spatial extension of the magnetization with respect to the spin
configuration of the Cooper pairs, resulting into clearcut anisotropy
signatures. A characteristic mark of the inverse proximity effect arises in the
induced spin-polarization at the TSC interface. This is unexpectedly stronger
when the magnetic proximity is weaker, thus unveiling immediate detection
signatures for spin-triplet pairs. We show that an anomalous magnetic proximity
can occur at the interface between the itinerant ferromagnet, SrRuO, and
the unconventional superconductor SrRuO. Such scenario indicates the
potential to design characteristic inverse proximity effects in experimentally
available SrRuO-SrRuO heterostructures and to assess the occurrence
of spin-triplet pairs in the highly debated superconducting phase of
SrRuO.Comment: 11 pages, 6 figure
l-Fucose Stimulates Utilization of d-Ribose by \u3cem\u3eEscherichia coli\u3c/em\u3e MG1655 ÎfucAO and \u3cem\u3eE. coli\u3c/em\u3e Nissle 1917 ÎfucAO Mutants in the Mouse Intestine and in M9 Minimal Medium
Escherichia coli MG1655 uses several sugars for growth in the mouse intestine. To determine the roles of l-fucose and d-ribose, an E. coli MG1655 ÎfucAO mutant and an E. coli MG1655 ÎrbsK mutant were fed separately to mice along with wild-type E. coli MG1655. The E. coli MG1655 ÎfucAO mutant colonized the intestine at a level 2 orders of magnitude lower than that of the wild type, but the E. coli MG1655 ÎrbsK mutant and the wild type colonized at nearly identical levels. Surprisingly, an E. coli MG1655 ÎfucAO ÎrbsK mutant was eliminated from the intestine by either wild-type E. coli MG1655 or E. coli MG1655 ÎfucAO, suggesting that the ÎfucAO mutant switches to ribose in vivo. Indeed, in vitro growth experiments showed that l-fucose stimulated utilization of d-ribose by the E. coli MG1655 ÎfucAO mutant but not by an E. coli MG1655 ÎfucK mutant. Since the ÎfucK mutant cannot convert l-fuculose to l-fuculose-1-phosphate, whereas the ÎfucAO mutant accumulates l-fuculose-1-phosphate, the data suggest that l-fuculose-1-phosphate stimulates growth on ribose both in the intestine and in vitro. An E. coli Nissle 1917 ÎfucAO mutant, derived from a human probiotic commensal strain, acted in a manner identical to that of E. coli MG1655 ÎfucAO in vivo and in vitro. Furthermore, l-fucose at a concentration too low to support growth stimulated the utilization of ribose by the wild-type E. coli strains in vitro. Collectively, the data suggest that l-fuculose-1-phosphate plays a role in the regulation of ribose usage as a carbon source by E. coli MG1655 and E. coli Nissle 1917 in the mouse intestine
Controlling magnetic exchange and anisotropy by non-magnetic ligand substitution in layered MPX3 (M = Ni, Mn; X = S, Se)
Recent discoveries in two-dimensional (2D) magnetism have intensified the
investigation of van der Waals (vdW) magnetic materials and further improved
our ability to tune their magnetic properties. Tunable magnetism has been
widely studied in antiferromagnetic metal thiophosphates MPX3. Substitution of
metal ions M has been adopted as an important technique to engineer the
magnetism in MPX3. In this work, we have studied the previously unexplored
chalcogen X substitutions in MPX3 (M = Mn/Ni; X = S/Se). We synthesized the
single crystals of MnPS3-xSex (0 < x < 3) and NiPS3-xSex (0 < x < 1.3) and
investigated the systematic evolution of the magnetism with varying x. Our
study reveals the effective tuning of magnetic interactions and anisotropies in
both MnPS3 and NiPS3 upon Se substitution. Such efficient engineering of the
magnetism provides a suitable platform to understand the low-dimensional
magnetism and develop future magnetic devices
Coupling charge and topological reconstructions at polar oxide interfaces
In oxide heterostructures, different materials are integrated into a single
artificial crystal, resulting in a breaking of inversion-symmetry across the
heterointerfaces. A notable example is the interface between polar and
non-polar materials, where valence discontinuities lead to otherwise
inaccessible charge and spin states. This approach paved the way to the
discovery of numerous unconventional properties absent in the bulk
constituents. However, control of the geometric structure of the electronic
wavefunctions in correlated oxides remains an open challenge. Here, we create
heterostructures consisting of ultrathin SrRuO, an itinerant ferromagnet
hosting momentum-space sources of Berry curvature, and LaAlO, a polar
wide-bandgap insulator. Transmission electron microscopy reveals an atomically
sharp LaO/RuO/SrO interface configuration, leading to excess charge being
pinned near the LaAlO/SrRuO interface. We demonstrate through
magneto-optical characterization, theoretical calculations and transport
measurements that the real-space charge reconstruction modifies the
momentum-space Berry curvature in SrRuO, driving a reorganization of the
topological charges in the band structure. Our results illustrate how the
topological and magnetic features of oxides can be manipulated by engineering
charge discontinuities at oxide interfaces.Comment: 5 pages main text (4 figures), 29 pages of supplementary informatio
Scale-Free model for governing universe dynamics
We investigate the effects of scale-free model on cosmology, providing, in
this way, a statistical background in the framework of general relativity. In
order to discuss properties and time evolution of some relevant universe
dynamical parameters (cosmographic parameters), such as (Hubble
parameter), (deceleration parameter), (jerk parameter) and
(snap parameter), which are well re-defined in the framework of scale-free
model, we analyze a comparison between WMAP data. Hence the basic purpose of
the work is to consider this statistical interpretation of mass distribution of
universe, in order to have a mass density dynamics, not inferred from
Friedmann equations, via scale factor . This model, indeed, has been used
also to explain a possible origin and a viable explanation of cosmological
constant, which assumes a statistical interpretation without the presence of
extended theories of gravity; hence the problem of dark energy could be
revisited in the context of a classical probability distribution of mass, which
is, in particular, for the scale-free model, , with
. The CDM model becomes, with these considerations, a
consequence of the particular statistics together with the use of general
relativity.Comment: 7 pages, 4 figure
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