1,025 research outputs found
(FeNi)GeTe: an antiferromagnetic triangular Ising lattice with itinerant magnetism
Based on first-principles calculations, an antiferromagnetic Ising model on a
triangular lattice has been proposed to interpret the order of Fe-Ge pairs
and the formation of superstructures in the
FeGeTe (F5GT), as well as to predict the existence of similar
superstructures in Ni doped F5GT (Ni-F5GT). Our study suggests that F5GT
systems may be considered as a structural realization of the well known
antiferromagnetic Ising model on a triangular lattice. Based on the
superstructures, a Heisenberg-Landau Hamiltonian, taking into account both
Heisenberg interactions and longitudinal spin fluctuations, is implemented to
describe magnetism in both F5GT and Ni-F5GT. We unveil that frustrated magnetic
interactions associated with Fe(1), tuned by a tiny Ni doping (),
is responsible for the experimentally observed enhancement of the to 478
K in Ni-F5GT. Our calculations show that at low doping levels, monolayer
Ni-F5GT has almost the same magnetic phase diagram as that of the bulk, which
indicates a pervasive beyond room temperature ferromagnetism in this Ni doped
two-dimensional system
Self-delivery of N-hydroxylethyl peptide assemblies to the cytosol inducing endoplasmic reticulum dilation in cancer cells
Inspired by clinical studies on alcohol abuse induced endoplasmic reticulum disruption, we designed a N-hydroxylethyl peptide assembly to regulate the ER stress response in cancer cells. Upon coupling with a coumarin derivative via an ester linkage, a prodrug was synthesized to promote esterase-facilitated self-delivery of N-hydroxylethyl peptide assemblies around the ER, inducing ER dilation. Following this, ER-specific apoptosis was effectively and efficiently activated in various types of cancer cells including drug resistant and metastatic ones
Bilayer two-orbital model of LaNiO under pressure
The newly discovered Ruddlesden-Popper bilayer LaNiO reaches an
remarkable superconducting transition temperature = 80 K under a pressure
of above 14 GPa. Here we propose a minimal bilayer two-orbital model of the
high-pressure phase of LaNiO. Our model is constructed with the
Ni-3d, 3d orbitals by using Wannier downfolding of the
density functional theory calculations, which captures the key ingredients of
the material, such as band structure and Fermi surface topology. There are two
electron pockets , and one hole pocket on the Fermi
surface, in which the , pockets show mixing of two orbitals,
while the pocket is associated with Ni-d orbital. The RPA
spin susceptibility reveals a magnetic enhancement associating to the
d state. A higher energy model with O-p orbitals is also provided
for further study
Enzyme-mediated dual-targeted-assembly realizes a synergistic anticancer effect
We designed and synthesized homochiral-peptide-based boron diketonate complexes. Co-administration of the two stereoisomers in cancer cells led to molecular assembly targeting both the plasma membrane and the lysosomes mediated via membrane-bonded enzymes. The dual-targeted-assembly generates a synergistic anticancer effect with amplified cancer spheroid toxicity and enhanced inhibition efficacy on cancer cell migration
Self-Assembly-Directed Cancer Cell Membrane Insertion of Synthetic Analogues for Permeability Alteration
Inspired by the metamorphosis of pore-forming toxins from soluble inactive monomers to cytolytic trans-membrane assemblies, we developed self-assembly-directed membrane insertion of synthetic analogues for permeability alteration. An expanded pi-conjugation-based molecular precursor with an extremely high rigidity and a long hydrophobic length that is comparable to the hydrophobic width of plasma membrane was synthesized for membrane-inserted self-assembly. Guided by the cancer biomarker expression in vitro, the soluble precursors transform into hydrophobic monomers forming assemblies inserted into the fluid phase of the membrane exclusively. Membrane insertion of rigid synthetic analogues destroys the selective permeability of the plasma membrane gradually. It eventually leads to cancer cell death, including drug resistant cancer cells
Superconductivity in the high-entropy ceramics Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2Cx with possible nontrivial band topology
Topological superconductors have drawn significant interest from the
scientific community due to the accompanying Majorana fermions. Here, we report
the discovery of electronic structure and superconductivity in high-entropy
ceramics Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2Cx (x = 1 and 0.8) combined with experiments
and first-principles calculations. The Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2Cx high-entropy
ceramics show bulk type-II superconductivity with Tc about 4.00 K (x = 1) and
2.65 K (x = 0.8), respectively. The specific heat jump is equal to 1.45 (x = 1)
and 1.52 (x = 0.8), close to the expected value of 1.43 for the BCS
superconductor in the weak coupling limit. The high-pressure resistance
measurements show that a robust superconductivity against high physical
pressure in Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2C, with a slight Tc variation of 0.3 K
within 82.5 GPa. Furthermore, the first-principles calculations indicate that
the Dirac-like point exists in the electronic band structures of
Ti0.2Zr0.2Nb0.2Mo0.2Ta0.2C, which is potentially a topological superconductor.
The Dirac-like point is mainly contributed by the d orbitals of transition
metals M and the p orbitals of C. The high-entropy ceramics provide an
excellent platform for the fabrication of novel quantum devices, and our study
may spark significant future physics investigations in this intriguing
material.Comment: 28 pages, 7 figures,The manuscript with the same title will be
published by Advanced Scienc
Single crystal growth and superconductivity in RbNiSe
We report the synthesis and characterization of RbNiSe, an analog of
the iron chalcogenide superconductor RbFeSe, via transport, angle
resolved photoemission spectroscopy, and density functional theory
calculations. A superconducting transition at = 1.20 K is identified.
In normal state, RbNiSe shows paramagnetic and Fermi liquid behaviors.
A large Sommerfeld coefficient yields a heavy effective electron mass of
. In the superconducting state, zero-field electronic
specific-heat data can be described by a two-gap BCS model, indicating
that RbNiSe is a multi-gap superconductor. Our density functional
theory calculations and angle resolved photoemission spectroscopy measurements
demonstrate that RbNiSe exhibits relatively weak correlations and
multi-band characteristics, consistent with the multi-gap superconductivity.Comment: 7 pages, 4 figure
Control cell migration by engineering integrin ligand assembly
Advances in mechanistic understanding of integrin-mediated adhesion highlight the importance of precise control of ligand presentation in directing cell migration. Top-down nanopatterning limited the spatial presentation to sub-micron placing restrictions on both fundamental study and biomedical applications. To break the constraint, here we propose a bottom-up nanofabrication strategy to enhance the spatial resolution to the molecular level using simple formulation that is applicable as treatment agent. Via self-assembly and co-assembly, precise control of ligand presentation is succeeded by varying the proportions of assembling ligand and nonfunctional peptide. Assembled nanofilaments fulfill multi-functions exerting enhancement to suppression effect on cell migration with tunable amplitudes. Self-assembled nanofilaments possessing by far the highest ligand density prevent integrin/actin disassembly at cell rear, which expands the perspective of ligand-density-dependent-modulation, revealing valuable inputs to therapeutic innovations in tumor metastasis
Orbital-Dependent Electron Correlation in Double-Layer Nickelate La3Ni2O7
The latest discovery of high temperature superconductivity near 80K in
La3Ni2O7 under high pressure has attracted much attention. Many proposals are
put forth to understand the origin of superconductivity. The determination of
electronic structures is a prerequisite to establish theories to understand
superconductivity in nickelates but is still lacking. Here we report our direct
measurement of the electronic structures of La3Ni2O7 by high-resolution
angle-resolved photoemmission spectroscopy. The Fermi surface and band
structures of La3Ni2O7 are observed and compared with the band structure
calculations. A flat band is formed from the Ni-3dz2 orbitals around the zone
corner which is 50meV below the Fermi level. Strong electron correlations are
revealed which are orbital- and momentum-dependent. Our observations will
provide key information to understand the origin of high temperature
superconductivity in La3Ni2O7.Comment: 18 pages, 4 figure
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