NMR Relaxivities of Paramagnetic Lanthanide-Containing Polyoxometalates.

The current trend for ultra-high-field magnetic resonance imaging (MRI) technologies opens up new routes in clinical diagnostic imaging as well as in material imaging applications. MRI selectivity is further improved by using contrast agents (CAs), which enhance the image contrast and improve specificity by the paramagnetic relaxation enhancement (PRE) mechanism. Generally, the efficacy of a CA at a given magnetic field is measured by its longitudinal and transverse relaxivities and , i.

Structural Insights into Hysteretic Spin-Crossover in a Set of Iron(II)-2,6-bis(1H-Pyrazol-1-yl)Pyridine) Complexes.

Bistable spin-crossover (SCO) complexes that undergo abrupt and hysteretic (ΔT ) spin-state switching are desirable for molecule-based switching and memory applications. In this study, we report on structural facets governing hysteretic SCO in a set of iron(II)-2,6-bis(1H-pyrazol-1-yl)pyridine) (bpp) complexes - [Fe(bpp-COOEt) ](X) ⋅CH NO (X=ClO , 1; X=BF , 2). Stable spin-state switching - T =288 K; ΔT =62 K - is observed for 1, whereas 2 undergoes above-room-temperature lattice-solvent content-dependent SCO - T =331 K; ΔT =43 K.

Clustered piperidinium-functionalized poly(terphenylene) anion exchange membranes with well-developed conductive nanochannels.

Anion exchange membrane fuel cells (AEMFCs) attract considerable attention owing to their high-power density and potential utilization of cheap non-noble metal catalysts. However, anion exchange membranes (AEMs) still face the problems of low conductivity, poor dimensional and chemical stability. To address these issues, AEMs with clustered piperidinium groups and ether-bond-free poly(terphenylene) backbone (3QPAP-x, x = 0.

Weak-Measurement-Induced Asymmetric Dephasing: Manifestation of Intrinsic Measurement Chirality.

Geometrical dephasing is distinct from dynamical dephasing in that it depends on the trajectory traversed, hence it reverses its sign upon flipping the direction in which the path is traced. Here we study sequences of generalized (weak) measurements that steer a system in a closed trajectory. The readout process is marked by fluctuations, giving rise to dephasing.

Optically Modulated HfS-Based Synapses for Artificial Vision Systems.

The simulation of human brain neurons by synaptic devices could be an effective strategy to break through the notorious "von Neumann Bottleneck" and "Memory Wall". Herein, opto-electronic synapses based on layered hafnium disulfide (HfS) transistors have been investigated. The basic functions of biological synapses are realized and optimized by modifying pulsed light conditions.

Breaking Symmetry Relaxes Structural and Magnetic Restraints, Suppressing QTM in Enantiopure Butterfly Fe Dy SMMs*.

The {Fe Dy } butterfly systems can show single molecule magnet (SMM) behaviour, the nature of which depends on details of the electronic structure, as previously demonstrated for the [Fe Dy (μ -OH) (Me-teaH) (O CPh) ] compound, where the [N,N-bis-(2-hydroxyethyl)-amino]-2-propanol (Me-teaH ) ligand is usually used in its racemic form. Here, we describe the consequences for the SMM properties by using enantiopure versions of this ligand and present the first homochiral 3d/4 f SMM, which could only be obtained for the S enantiomer of the ligand for [Fe Dy (μ -OH) (Me-teaH) (O CPh) ] since the R enantiomer underwent significant racemisation. To investigate this further, we prepared the [Fe Dy (μ -OH) (Me-teaH) (O CPh) (NO ) ] version, which could be obtained as the RS-, R- and S-compounds.

Critical current fluctuations in graphene Josephson junctions.

We have studied 1/f noise in critical current [Formula: see text] in h-BN encapsulated monolayer graphene contacted by NbTiN electrodes. The sample is close to diffusive limit and the switching supercurrent with hysteresis at Dirac point amounts to [Formula: see text] nA. The low frequency noise in the superconducting state is measured by tracking the variation in magnitude and phase of a reflection carrier signal [Formula: see text] at 600-650 MHz.

Terminal Ligand and Packing Effects on Slow Relaxation in an Isostructural Set of [Dy(H dapp)X ] Single Molecule Magnets*.

We report three structurally related single ion Dy compounds using the pentadentate ligand 2,6-bis((E)-1-(2-(pyridin-2-yl)-hydrazineylidene)ethyl)pyridine (H dapp) [Dy(H dapp)(NO ) ]NO (1), [Dy(H dapp)(OAc) ]Cl (2) and [Dy(H dapp)(NO ) ]Cl (NO ) (3). The (H dapp) occupies a helical twisted pentagonal equatorial arrangement with two anionic ligands in the axial positions. Further influence on the electronic and magnetic structure is provided by a closely associated counterion interacting with the central N-H group of the (H dapp).

Indirect Spin-Readout of Rare-Earth-Based Single-Molecule Magnet with Scanning Tunneling Microscopy.

Rare-earth based single-molecule magnets are promising candidates for magnetic information storage including qubits as their large magnetic moments are carried by localized 4f electrons. This shielding from the environment in turn hampers a direct electronic access to the magnetic moment. Here, we present the indirect readout of the Dy moment in Bis(phthalocyaninato)dysprosium (DyPc_{2}) molecules on Au(111) using milli-Kelvin scanning tunneling microscopy.

From the {Fe Ln } Butterfly's Perspective: the Magnetic Benefits and Challenges of Cooperativity within 3 d-4 f Based Coordination Clusters.

In this Review we discuss the tuning handles which can be used to steer the magnetic properties of Fe -4 f "butterfly" compounds. The majority of presented compounds were produced in the context of project A3 "Di- to tetranuclear compounds incorporating highly anisotropic paramagnetic metal ions" within the SFB/TRR88 "3MET". These contain {Fe Ln } cores encapsulated in ligand shells which are easy to tune in a "test-bed" system.

Strange bedfellows inside a superconductor.

An unexpected link is found between the “strange metal” phase and charge density waves.

Assisted Self-Assembly to Target Heterometallic Mn-Nd and Mn-Sm SMMs: Synthesis and Magnetic Characterisation of [Mn Ln (O) (OH) (mdea) (piv) (NO ) ] (Ln=Nd, Sm, Eu, Gd)*.

In an assisted self-assembly approach starting from the [Mn O (piv) (4-Me-py) (pivH) ] cluster a family of Mn-Ln compounds (Ln=Pr-Yb) was synthesised. The reaction of [Mn O (piv) (4-Me-py) (pivH) ] (1) with N-methyldiethanolamine (mdeaH ) and Ln(NO )  ⋅ 6H O in MeCN generally yields two main structure types: for Ln=Tb-Yb a previously reported Mn Ln motif is obtained, whereas for Ln=Pr-Eu a series of Mn Ln clusters is obtained. Within this series the Gd analogue represents a special case because it shows both structural types as well as a third Mn Ln inverse butterfly motif.

InO:H-Based Hole-Transport-Layer-Free Tin/Lead Perovskite Solar Cells for Efficient Four-Terminal All-Perovskite Tandem Solar Cells.

Narrow-band gap (NBG) Sn-Pb perovskites with band gaps of ∼1.2 eV, which correspond to a broad photon absorption range up to ∼1033 nm, are highly promising candidates for bottom solar cells in all-perovskite tandem photovoltaics. To exploit their potential, avoiding optical losses in the top layer stacks of the tandem configuration is essential.

Ni -Containing 54-Tungsto-6-Silicate: Synthesis, Structure, Magnetic and Electrochemical Studies.

The 36-Ni -containing 54-tungsto-6-silicate, [Ni (OH) (H O) (SiW O ) ] (Ni ) was synthesized by a simple one-pot reaction of the Ni -pivalate complex [Ni (μ-OH )(O CCMe ) (HO CCMe ) ] with the trilacunary [SiW O ] polyanion precursor in water and structurally characterized by a multitude of physicochemical techniques including single-crystal XRD, FTIR, TGA, elemental analysis, magnetic and electrochemical studies. Polyanion Ni comprises six equivalent {Ni SiW } units which are linked by Ni-O-W bridges forming a macrocyclic assembly. Magnetic studies demonstrate that the {Ni } building blocks in Ni remain magnetically intact while forming a hexagonal ring with antiferromagnetic exchange interactions between adjacent {Ni } units.

Fused-Silica 3D Chiral Metamaterials via Helium-Assisted Microcasting Supporting Topologically Protected Twist Edge Resonances with High Mechanical Quality Factors.

It is predicted theoretically that a 1D diatomic chain of 3D chiral cells can support a topological bandgap that allows for translating a small time-harmonic axial movement at one end of the chain into a resonantly enhanced large rotation of an edge state at the other end. This edge state is topologically protected such that an arbitrary mass of a mirror at the other end does not shift the eigenfrequency out of the bandgap. Herein, this complex 3D laser-beam-scanner microstructure is realized in fused-silica form.

Emerging symmetric strain response and weakening nematic fluctuations in strongly hole-doped iron-based superconductors.

Electronic nematicity is often found in unconventional superconductors, suggesting its relevance for electronic pairing. In the strongly hole-doped iron-based superconductors, the symmetry channel and strength of the nematic fluctuations, as well as the possible presence of long-range nematic order, remain controversial. Here, we address these questions using transport measurements under elastic strain.

Anomalous Hydrodynamics in a One-Dimensional Electronic Fluid.

We construct multimode viscous hydrodynamics for one-dimensional spinless electrons. Depending on the scale, the fluid has six (shortest lengths), four (intermediate, exponentially broad regime), or three (asymptotically long scales) hydrodynamic modes. Interaction between hydrodynamic modes leads to anomalous scaling of physical observables and waves propagating in the fluid.

Chiral Resolution of Spin-Crossover Active Iron(II) [2x2] Grid Complexes.

Chiral magnetic materials are proposed for applications in second-order non-linear optics, magneto-chiral dichroism, among others. Recently, we have reported a set of tetra-nuclear Fe(II) grid complex conformers with general formula C/S-[Fe L ] (L: 2,6-bis(6-(pyrazol-1-yl)pyridin-2-yl)-1,5-dihydrobenzo[1,2-d : 4,5-d']diimidazole). In the grid complexes, isomerism emerges from tautomerism and conformational isomerism of the ligand L, and the S-type grid complex is chiral, which originates from different non-centrosymmetric spatial organization of the trans type ligand around the Fe(II) center.

Dynamic control of Purcell enhanced emission of erbium ions in nanoparticles.

The interaction of single quantum emitters with an optical cavity enables the realization of efficient spin-photon interfaces, an essential resource for quantum networks. The dynamical control of the spontaneous emission rate of quantum emitters in cavities has important implications in quantum technologies, e.g.

Vanishing Thermal Equilibration for Hole-Conjugate Fractional Quantum Hall States in Graphene.

Transport through edge channels is responsible for conduction in quantum Hall (QH) phases. Robust quantized values of charge and thermal conductances dictated by bulk topology appear when equilibration processes become dominant. We report on measurements of electrical and thermal conductances of integer and fractional QH phases, realized in hexagonal boron nitride encapsulated graphite-gated bilayer graphene devices for both electron and hole doped sides with different valley and orbital symmetries.

Photon Transport in a Bose-Hubbard Chain of Superconducting Artificial Atoms.

We demonstrate nonequilibrium steady-state photon transport through a chain of five coupled artificial atoms simulating the driven-dissipative Bose-Hubbard model. Using transmission spectroscopy, we show that the system retains many-particle coherence despite being coupled strongly to two open spaces. We find that cross-Kerr interaction between system states allows high-contrast spectroscopic visualization of the emergent energy bands.

Ballistic Graphene Cooper Pair Splitter.

We report an experimental study of a Cooper pair splitter based on ballistic graphene multiterminal junctions. In a two transverse junction geometry, namely the superconductor-graphene-superconductor and the normal metal-graphene-normal metal, we observe clear signatures of Cooper pair splitting in the local as well as nonlocal electronic transport measurements. Our experimental data can be very well described by our beam splitter model.

Optical spin-state polarization in a binuclear europium complex towards molecule-based coherent light-spin interfaces.

The success of the emerging field of solid-state optical quantum information processing (QIP) critically depends on the access to resonant optical materials. Rare-earth ion (REI)-based molecular systems, whose quantum properties could be tuned taking advantage of molecular engineering strategies, are one of the systems actively pursued for the implementation of QIP schemes. Herein, we demonstrate the efficient polarization of ground-state nuclear spins-a fundamental requirement for all-optical spin initialization and addressing-in a binuclear Eu(III) complex, featuring inhomogeneously broadened D →F optical transition.

Short-Range Nematic Fluctuations in Sr_{1-x}Na_{x}Fe_{2}As_{2} Superconductors.

Interactions between nematic fluctuations, magnetic order and superconductivity are central to the physics of iron-based superconductors. Here we report on in-plane transverse acoustic phonons in hole-doped Sr_{1-x}Na_{x}Fe_{2}As_{2} measured via inelastic x-ray scattering, and extract both the nematic susceptibility and the nematic correlation length. By a self-contained method of analysis, for the underdoped (x=0.