Rocksalt-type heavy rare earth monoxides TbO, DyO, and ErO exhibiting metallic electronic states and ferromagnetism.

Solid-phase rare earth monoxides have been recently synthesized thin film epitaxy. However, it has been difficult to synthesize heavy rare earth monoxides owing to their severe chemical instability. In this study, rocksalt-type heavy rare earth monoxides REOs (RE = Tb, Dy, Er) were synthesized for the first time, as single-phase epitaxial thin films.

Magnetic Supramolecular Spherical Arrays: Direct Formation of Micellar Cubic Mesophase by Lanthanide Metallomesogens with 7-Coordination Geometry.

Here, an unprecedented phenomenon in which 7-coordinate lanthanide metallomesogens, which align via hydrogen bonds mediated by coordinated HO molecules, form micellar cubic mesophases at room temperature, creating body-centered cubic (BCC)-type supramolecular spherical arrays, is reported. The results of experiments and molecular dynamics simulations reveal that spherical assemblies of three complexes surrounded by an amorphous alkyl domain spontaneously align in an energetically stable orientation to form the BCC structure. This phenomenon differs greatly from the conventional self-assembling behavior of 6-coordinated metallomesogens, which form columnar assemblies due to strong intermolecular interactions.

Layer-Number-Independent Two-Dimensional Ferromagnetism in CrTe.

In a conventional magnetic material, a long-range magnetic order develops in three dimensions, and reducing a layer number weakens its magnetism. Here we demonstrate anomalous layer-number-independent ferromagnetism down to the two-dimensional (2D) limit in a metastable phase of CrTe. We fabricated CrTe thin films by molecular-beam epitaxy and found that CrTe could host two distinct ferromagnetic phases characterized with different Curie temperatures ().

The ligand field in low-crystallinity metal-organic frameworks investigated by soft X-ray core-level absorption spectroscopy.

The ligand field (LF) of transition metal ions is a crucial factor in realizing the mechanism of novel physical and chemical properties. However, the low-crystallinity state, including the amorphous state, precludes the clarification of the electronic structural relationship of transition metal ions using crystallographic techniques, ultraviolet and infrared optical methods, and magnetometry. Here, we demonstrate that soft X-ray 2p → 3d core-level absorption spectroscopy (-edge XAS) systematically revealed the local 3d electronic states, including in the LF, of nitrogen-coordinated transition-metal ions for low-crystallinity cyanide-bridged metal-organic frameworks (MOFs) [Ni(CN)] (MNi; = Mn, Fe, Co, Ni) and Ni[Pd(CN)] (NiPd).

Hole Dynamics in Photoexcited Hematite Studied with Femtosecond Oxygen K-edge X-ray Absorption Spectroscopy.

Hematite (α-FeO) is a photoelectrode for the water splitting process because of its relatively narrow bandgap and abundance in the earth's crust. In this study, the photoexcited state of a hematite thin film was investigated with femtosecond oxygen K-edge X-ray absorption spectroscopy (XAS) at the PAL-XFEL in order to follow the dynamics of its photoexcited states. The 200 fs decay time of the hole state in the valence band was observed via its corresponding XAS feature.

Equation of states for dense ice up to 80 GPa at low-temperature conditions.

We have measured the lattice volume of ice VIII in different pressure-temperature pathways and found that the volume depends on the pathway, implying that deviatoric stress makes the volume larger. Dense ice is in the ice VIII phase with the molar volume of 6.56 cm and in a high-pressure phase with the molar volume of 6.

Femtosecond Charge Density Modulations in Photoexcited CuWO.

Copper tungstate (CuWO) is an important semiconductor with a sophisticated and debatable electronic structure that has a direct impact on its chemistry. Using the PAL-XFEL source, we study the electronic dynamics of photoexcited CuWO. The Cu L X-ray absorption spectrum shifts to lower energy upon photoexcitation, which implies that the photoexcitation process from the oxygen valence band to the tungsten conduction band effectively increases the charge density on the Cu atoms.

Coordination Geometry Changes in Amorphous Cyanide-Bridged Metal-Organic Frameworks upon Water Adsorption.

Amorphous coordination polymers and metal-organic frameworks (MOFs) have attracted much attention owing to their various functionalities. Here, we demonstrate the tunable water adsorption behavior of a series of amorphous cyanide-bridged MOFs with different metals (M[Ni(CN)]: ; M = Mn, Fe, and Co). All three compounds adsorb up to six water molecules at a certain vapor pressure () and undergo conversion to crystalline Hofmann-type MOFs, M(HO)[Ni(CN)]·4HO (; M = Mn, Fe, and Co).

Spin-Orbit-Induced Ising Ferromagnetism at a van der Waals Interface.

Magnetocrystalline anisotropy, a key ingredient for establishing long-range order in a magnetic material down to the two-dimensional (2D) limit, is generally associated with spin-orbit interaction (SOI) involving a finite orbital angular momentum. Here we report strong out-of-plane magnetic anisotropy without orbital angular momentum, emerging at the interface between two different van der Waals (vdW) materials, an archetypal metallic vdW material NbSe possessing Zeeman-type SOI and an isotropic vdW ferromagnet VSe. We found that the Zeeman SOI in NbSe induces robust out-of-plane magnetic anisotropy in VSe down to the 2D limit with a more than 2-fold enhancement of the transition temperature.

Red-Fluorescent Pt Nanoclusters for Detecting and Imaging HER2 in Breast Cancer Cells.

Overexpression of human epidermal growth factor receptor 2 (HER2) is associated with more frequent cancer recurrence and metastasis. Sensitive sensing of HER2 in living breast cancer cells is crucial in the early stages of cancer and to further understand its role in cells. Biomedical imaging has become an indispensable tool in the fields of early cancer diagnosis and therapy.

Intrinsic 2D Ferromagnetism in VSe Epitaxial Thin Films.

The discoveries of intrinsic ferromagnetism in atomically thin van der Waals crystals have opened a new research field enabling fundamental studies on magnetism at two-dimensional (2D) limit as well as development of magnetic van der Waals heterostructures. Currently, a variety of 2D ferromagnetism has been explored mainly by mechanically exfoliating "originally ferromagnetic (FM)" van der Waals crystals, while a bottom-up approach by thin-film growth technique has demonstrated emergent 2D ferromagnetism in a variety of "originally non-FM" van der Waals materials. Here we demonstrate that VSe epitaxial thin films grown by molecular-beam epitaxy exhibit emergent 2D ferromagnetism with intrinsic spin polarization of the V 3d electrons despite that the bulk counterpart is "originally antiferromagnetic".

Direct observation of the electronic states of photoexcited hematite with ultrafast 2p3d X-ray absorption spectroscopy and resonant inelastic X-ray scattering.

Hematite, α-FeO, is an important semiconductor for photoelectrochemical water splitting. Its low charge carrier mobility and the presence of midgap states provide favourable conditions for electron-hole recombination, hence affecting the semiconductor's photoelectrochemical efficiency. The nature of the excited state and charge carrier transport in hematite is strongly debated.

High pressure synthesis of a quasi-one-dimensional GdFeO-type perovskite PrCuO with nearly divalent Cu ions.

A new perovskite-type cuprate PrCuO has been synthesized by high-pressure oxygen annealing. Synchrotron X-ray powder diffraction and absorption spectroscopy revealed that PrCuO crystallizes in the GdFeO-type structure with cooperative Jahn-Teller distortion, forming one-dimensional chains of corner-shared CuO plaquettes with nearly divalent Cu ions.

Iron resonant photoemission spectroscopy on anodized hematite points to electron hole doping during anodization.

Anodization of α-Fe(2)O(3) (hematite) electrodes in alkaline electrolyte under constant potential conditions the electrode surface in a way that an additional current wave occurs in the cyclic voltammogram. The energy position of this current wave is closely below the potential of the anodization treatment. Continued cycling or exchanging of the electrolyte causes depletion of this new feature.