86 research outputs found
Dimensionality-confined superconductivity within SrNbO3-SrTiO3 heterostructures
Interfaces between transition-metal oxides are able to host two-dimensional
electron gases (2DEGs) and exhibit exotic quantum phenomena. Here we report the
observation of superconductivity below 230 mK for the heterostructure composed
of SrNbO3 (SNO) and SrTiO3 (STO). Different from some other counterparts with
two insulators, the metallic SNO provides a novel mechanism to form a quasi
2DEG by charge transfer from bulk towards interface under strain. The
superconductivity, residing within the strained SNO layer near the interface,
is contributed by an electron system with record-low carrier density. Notably,
although embedded in a normal metallic layer with a carrier density 4 to 5
orders higher, the electron system is still uniquely well-protected to retain
high mobility and lies deep in extreme quantum regime
Age-Related Changes on CD40 Promotor Methylation and Immune Gene Expressions in Thymus of Chicken
One hundred and twenty one-day-old breeder cocks, included 15 cages of 8 birds each, were fed to learn the aging's effect on chicken's thymus immunity. At 2 (2-W) and 40 (40-W) weeks of age, one chicken each cage was randomly chosen and slaughtered to get the thymus sample. The results showed that thymus weight and morphology of 40-W group were far different from that of 2-W group, and exhibited a property of degeneration. Considering this phenotype variance, we analyzed the thymus' transcriptome to investigate the molecular mechanism that had been implicated in this phenotype diversity with age. Pearson correlation coefficients and principal component analysis indicated that two major populations corresponding to 40-W and 2-W group were identified, and 1949 differentially expressed genes (DEGs, 1722 up-regulated and 127 down-regulated) were obtained. Results of GO and KEGG pathway enrichment found that 4 significantly enriched KEGG pathways (Cytokine-cytokine receptor interaction, Intestinal immune network for IgA production, Toll-like receptor signaling pathway, AGE-RAGE signaling pathway in diabetic complications) related to immunoregulation were screened between 40-W and 2-W group. These results confirmed that thymus immunity of chickens had a strong age-related correlation. DEGs related to these 4 enriched KEGG pathways were suppressed in the thymus of 2-W group, this indicated that thymus immunity of 2-weeks-age chick was down-regulated. CD40 is involved in 3 of the 4 significantly enriched pathways, and it is critical for thymus immune-regulation. CD40 promoter methylation level of 2-W group was higher than that of 40-W group, it is consistent with the transcriptional differences of the gene. Our study concluded that thymus immunity of chicken was varied with age. Compared to the 40-W group, thymus immunity of 2-W group was down-regulated, and in a status of hypo-activation on the whole, and these effects might be related to CD40 suppression induced by promoter hyper-methylation of the gene
Super-tetragonal Sr4Al2O7: a versatile sacrificial layer for high-integrity freestanding oxide membranes
Releasing the epitaxial oxide heterostructures from substrate constraints
leads to the emergence of various correlated electronic phases and paves the
way for integrations with advanced semiconductor technologies. Identifying a
suitable water-soluble sacrificial layer, compatible with the high-quality
epitaxial growth of oxide heterostructures, is currently the key to the
development of large-scale freestanding oxide membranes. In this study, we
unveil the super-tetragonal Sr4Al2O7 (SAOT) as a promising water-soluble
sacrificial layer. The distinct low-symmetric crystal structure of SAOT enables
a superior capability to sustain epitaxial strain, thus allowing for broad
tunability in lattice constants. The resultant structural coherency and
defect-free interface in perovskite ABO3/SAOT heterostructures effectively
restrain crack formations during the water-assisted release of freestanding
oxide membranes. For a variety of non-ferroelectric oxide membranes, the
crack-free areas can span up to a few millimeters in length scale. These
compelling features, combined with the inherent high-water solubility, make
SAOT a versatile and feasible sacrificial layer for producing high-quality
freestanding oxide membranes, thereby boosting their potential for innovative
oxide electronics and flexible device designs.Comment: 5 figures and SI, it is the second version of this manuscrip
Strain mediated phase crossover in Ruddlesden Popper nickelates
Recent progress on the signatures of pressure-induced high temperature
superconductivity in Ruddlesden Popper (RP) nickelates (Lan+1NinO3n+1) has
attracted growing interest in both theoretical calculations and experimental
efforts. The fabrication of high-quality single crystalline RP nickelate thin
films is critical for possible reducing the superconducting transition pressure
and advancing applications in microelectronics in the future. In this study, we
report the observations of an active phase transition in RP nickelate films
induced by misfit strain. We found that RP nickelate films favor the perovskite
structure (n = infinite) under tensile strains, while compressive strains
stabilize the La3Ni2O7 (n = 2) phase. The selection of distinct phases is
governed by the strain dependent formation energy and electronic configuration.
In compressively strained La3Ni2O7, we experimentally determined splitting
energy is ~0.2 eV and electrons prefer to occupy in-plane orbitals. First
principles calculations unveil a robust coupling between strain effects and the
valence state of Ni ions in RP nickelates, suggesting a dual driving force for
the inevitable phase co-existence transition in RP nickelates. Our work
underscores the sensitivity of RP nickelate formation to epitaxial strain,
presenting a significant challenge in fabricating pure-phase RP nickelate
films. Therefore, special attention to stacking defects and grain boundaries
between different RP phases is essential when discussing the pressure-induced
superconductivity in RP nickelates.Comment: 29 pages, 5 figures, one supplementary material
Genome-Wide Linkage and Association Study of Childhood Gender Nonconformity in Males.
Male sexual orientation is influenced by environmental and complex genetic factors. Childhood gender nonconformity (CGN) is one of the strongest correlates of homosexuality with substantial familiality. We studied brothers in families with two or more homosexual brothers (409 concordant sibling pairs in 384 families, as well as their heterosexual brothers), who self-recalled their CGN. To map loci for CGN, we conducted a genome-wide linkage scan (GWLS) using SNP genotypes. The strongest linkage peaks, each with significant or suggestive two-point LOD scores and multipoint LOD score support, were on chromosomes 5q31 (maximum two-point LOD = 4.45), 6q12 (maximum two-point LOD = 3.64), 7q33 (maximum two-point LOD = 3.09), and 8q24 (maximum two-point LOD = 3.67), with the latter not overlapping with previously reported strongest linkage region for male sexual orientation on pericentromeric chromosome 8. Family-based association analyses were used to identify associated variants in the linkage regions, with a cluster of SNPs (minimum association p = 1.3 × 10-8) found at the 5q31 linkage peak. Genome-wide, clusters of multiple SNPs in the 10-6 to 10-8 p-value range were found at chromosomes 5p13, 5q31, 7q32, 8p22, and 10q23, highlighting glutamate-related genes. This is the first reported GWLS and genome-wide association study on CGN. Further increasing genetic knowledge about CGN and its relationships to male sexual orientation should help advance our understanding of the biology of these associated traits
Syntropic spin alignment at the interface between ferromagnetic and superconducting nitrides
The magnetic correlations at the superconductor/ferromagnet (S/F) interfaces
play a crucial role in realizing dissipation-less spin-based logic and memory
technologies, such as triplet-supercurrent spin-valves and "{\pi}" Josephson
junctions. Here we report the coexistence of an induced large magnetic moment
and a crypto ferromagnetic state at high-quality nitride S/F interfaces. Using
polarized neutron reflectometry and d. c. SQUID measurements, we quantitatively
determined the magnetization profile of S/F bilayer and confirmed the induced
magnetic moment in the adjacent superconductor only exists below TC.
Interestingly, the direction of the induced moment in the superconductors was
unexpectedly parallel to that in the ferromagnet, which contrasts with earlier
findings in S/F heterostructures based on metals or oxides. The
first-principles calculations verify the observed unusual interfacial spin
texture is caused by the Heisenberg direct exchange coupling through d orbital
overlapping and severe charge transfer across the interfaces. Our work
establishes an incisive experimental probe for understanding the magnetic
proximity behavior at S/F interfaces and provides a prototype epitaxial
building block for superconducting spintronics.Comment: 21 pages, 5 figures, supplementary file with 14 figure
Metal-to-insulator transition in oxide semimetals by anion doping
Oxide semimetals exhibiting both nontrivial topological characteristics stand
as exemplary parent compounds and multiple degrees of freedom, offering great
promise for the realization of novel electronic states. In this study, we
present compelling evidence of profound structural and transport phase shifts
in a recently uncovered oxide semimetal, SrNbO3, achieved through effective
in-situ anion doping. Notably, a remarkable increase in resistivity of more
than three orders of magnitude at room temperature is observed upon
nitrogen-doping. The extent of electronic modulation in SrNbO3 is strongly
correlated with the misfit strain, underscoring its phase instability to both
chemical doping and crystallographic symmetry variations. Using
first-principles calculations, we discern that elevating the level of nitrogen
doping induces an upward shift in the conductive bands of SrNbO3-dNd.
Consequently, a transition from a metallic state to an insulating state becomes
apparent as the nitrogen concentration reaches a threshold of 1/3. This
investigation sheds light on the potential of anion engineering in oxide
semimetals, offering pathways for manipulating their physical properties. These
insights hold promise for future applications that harness these materials for
tailored functionalities.Comment: 18 pages, 4 figure
Large-scale GWAS reveals insights into the genetic architecture of same-sex sexual behavior.
Twin and family studies have shown that same-sex sexual behavior is partly genetically influenced, but previous searches for specific genes involved have been underpowered. We performed a genome-wide association study (GWAS) on 477,522 individuals, revealing five loci significantly associated with same-sex sexual behavior. In aggregate, all tested genetic variants accounted for 8 to 25% of variation in same-sex sexual behavior, only partially overlapped between males and females, and do not allow meaningful prediction of an individual's sexual behavior. Comparing these GWAS results with those for the proportion of same-sex to total number of sexual partners among nonheterosexuals suggests that there is no single continuum from opposite-sex to same-sex sexual behavior. Overall, our findings provide insights into the genetics underlying same-sex sexual behavior and underscore the complexity of sexuality
- …