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$_3$, and the unconventional superconductor Sr$_2$RuO$_4$. Such scenario indicates the potential to design characteristic inverse proximity effects in experimentally available SrRuO$_3$-Sr$_2$RuO$_4$ heterostructures and to assess the occurrence of spin-triplet pairs in the highly debated superconducting phase of Sr$_2$RuO$_4$.Comment: 11 pages, 6 figure

l-Fucose Stimulates Utilization of d-Ribose by \u3cem\u3eEscherichia coli\u3c/em\u3e MG1655 ΔfucAO and \u3cem\u3eE. coli\u3c/em\u3e Nissle 1917 ΔfucAO 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 ΔfucAO mutant and an E. coli MG1655 ΔrbsK mutant were fed separately to mice along with wild-type E. coli MG1655. The E. coli MG1655 ΔfucAO mutant colonized the intestine at a level 2 orders of magnitude lower than that of the wild type, but the E. coli MG1655 ΔrbsK mutant and the wild type colonized at nearly identical levels. Surprisingly, an E. coli MG1655 ΔfucAO ΔrbsK mutant was eliminated from the intestine by either wild-type E. coli MG1655 or E. coli MG1655 ΔfucAO, suggesting that the ΔfucAO 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 ΔfucAO mutant but not by an E. coli MG1655 ΔfucK mutant. Since the ΔfucK mutant cannot convert l-fuculose to l-fuculose-1-phosphate, whereas the ΔfucAO 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 ΔfucAO mutant, derived from a human probiotic commensal strain, acted in a manner identical to that of E. coli MG1655 ΔfucAO 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$_3$, an itinerant ferromagnet hosting momentum-space sources of Berry curvature, and LaAlO$_3$, a polar wide-bandgap insulator. Transmission electron microscopy reveals an atomically sharp LaO/RuO$_2$/SrO interface configuration, leading to excess charge being pinned near the LaAlO$_3$/SrRuO$_3$ 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$_3$, 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 $H(t)$ (Hubble parameter), $q(t)$ (deceleration parameter), $j(t)$ (jerk parameter) and $s(t)$ (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 $\rho$ dynamics, not inferred from Friedmann equations, via scale factor $a(t)$. 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, $P(k)\sim k^{-\gamma}$, with $2<\gamma<3$. The $\Lambda$CDM model becomes, with these considerations, a consequence of the particular statistics together with the use of general relativity.Comment: 7 pages, 4 figure