In transition metal compounds, due to the interplay of charge, spin, lattice and orbital degrees of freedom, many intertwined orders exist with close energies. One of the commonly observed states is the so-called nematic electron state, which breaks the in-plane rotational symmetry. This nematic state appears in cuprates, iron-based superconductor, etc. Nematicity may coexist, affect, cooperate or compete with other orders. Here we show the anisotropic in-plane electronic state and superconductivity in a recently discovered kagome metal CsV3Sb5 by measuring c-axis resistivity with the in-plane rotation of magnetic field. We observe a twofold symmetry of superconductivity in the superconducting state and a unique in-plane nematic electronic state in normal state when rotating the in-plane magnetic field. Interestingly these two orders are orthogonal to each other in terms of the field direction of the minimum resistivity. Our results shed new light in understanding non-trivial physical properties of CsV3Sb5.

In transition metal compounds, due to the interplay of charge, spin, lattice and orbital degrees of freedom, many intertwined orders exist with close energies. One of the commonly observed states is the so-called nematic electron state, which breaks the in-plane rotational symmetry. This nematic state appears in cuprates, iron based superconductor, etc. Nematicity may coexist, affect, cooperate or compete with other orders. Here we show the anisotropic in-plane electronic state and superconductivity in a recently discovered kagome metal CsV3Sb5 by measuring c-axis resistivity with the in-plane rotation of magnetic field. We observe a twofold symmetry of superconductivity in the superconducting state and a unique in-plane nematic electronic state in normal state when rotating the in-plane magnetic field. Interestingly these two orders are orthogonal to each other in terms of the field direction of the minimum resistivity. Our results shed new light in understanding non-trivial physical properties of CsV3Sb5.

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Superconductivity with transition temperature T c above 40 K was observed in protonated FeSe (H y -FeSe) previously with the ionic liquid EMIM-BF 4 used in the electrochemical process. However, the real superconducting phase is not clear until now. And detailed structural, magnetization, and electrical transport measurements are lacking. By using similar protonating technique on FeSe single crystals, we obtain superconducting samples with T c above 40 K. We show that the obtained superconducting phase is not H y -FeSe but actually an organic-ion (C 6 H 11 N + 2 referred to as EMIM + )-intercalated phase (EMIM) x FeSe. By using x-ray diffraction technique, two sets of index peaks corresponding to different c-axis lattice constants are detected in the obtained samples, which belong to the newly formed phase of intercalated (EMIM) x FeSe and the residual FeSe, respectively. The superconductivity of (EMIM) x FeSe with T c of 44.4 K is confirmed by resistivity and magnetic susceptibility measurements. Temperature dependence of resistivity with different applied magnetic fields reveals that the upper critical field H c2 is quite high, while the irreversibility field H irr is suppressed quickly with increasing temperature till about 20 K. This indicates that the resultant compound has a high anisotropy with a large spacing between the FeSe layers.

The diffusion behaviors of Co clusters on clean ZnO(0001)-Zn single crystal surface and their magnetic properties are studied. Co clusters are deposited on the clean ZnO(0001)-Zn surface at room temperature and then undergone ultrahigh vacuum annealing until fully reconstructed. The replacement of Zn2+ by Co2+ is confirmed by scanning tunneling microscopy and x-ray photoelectron spectroscopy. The Co doped ZnO shows a weak ferromagnetism at room temperature with a saturation magnetic moment of 1.08 μB/Co. Our observations indicate that surface Zn vacancies facilitate Co diffusion, and the interplay of Co ion with internal O vacancies leads to the ferromagnetism.

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MoS 2 is a typical two-dimensional material with promising optical and electrical properties. The realization of ferromagnetism in MoS 2 is important for its applications in semiconductor spintronics. A facile technique should be developed to induce the ferromagnetism in MoS 2 , and the possible extrinsic contribution should be avoided. In this paper, flower-like MoS 2 nanostructures were fabricated by the hydrothermal method. X-ray diffraction spectra show the 1 T/2H mixed phases of as-prepared MoS 2 nanostructures, which changes to pure 2H structure after the O plasma treatment. Raman spectra confirm the existence of Mo-O bonding, which is further confirmed by the X-ray photoelectron spectra after the O plasma treatment. Magnetization measurements at 300 K show the weak ferromagnetism in the as-prepared MoS 2 , with saturated ferromagnetic magnetization of 0.0012 emu/g. After the O plasma treatment, the weak ferromagnetism is strongly enhanced with saturated ferromagnetic magnetization of 0.0343 emu/g. First principle calculation has been performed to disclose the possible origin of ferromagnetism. Significant overlapping between the density of states of O and Mo, or O and S has been observed. The magnetic contribution from Mo and S is negligible, while O takes the main role for the enhanced ferromagnetism.

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