Magnetochiral tunneling in paramagnetic Co1/3NbS2.

Electric currents have the intriguing ability to induce magnetization in nonmagnetic crystals with sufficiently low crystallographic symmetry. Some associated phenomena include the non-linear anomalous Hall effect in polar crystals and the nonreciprocal directional dichroism in chiral crystals when magnetic fields are applied. In this work, we demonstrate that the same underlying physics is also manifested in the electronic tunneling process between the surface of a nonmagnetic chiral material and a magnetized scanning probe. In the paramagnetic but chiral metallic compound Co1/3NbS2, the magnetization induced by the tunneling current is shown to become detectable by its coupling to the magnetization of the tip itself. This results in a contrast across different chiral domains, achieving atomic-scale spatial resolution of structural chirality. To support the proposed mechanism, we used first-principles theory to compute the chirality-dependent current-induced magnetization and Berry curvature in the bulk of the material. Our demonstration of this magnetochiral tunneling effect opens up an avenue for investigating atomic-scale variations in the local crystallographic symmetry and electronic structure across the structural domain boundaries of low-symmetry nonmagnetic crystals.

Tunable Single-Atomic Charges on a Cleaved Intercalated Transition Metal Dichalcogenide.

Control of a single ionic charge state by altering the number of bound electrons has been considered as an ultimate testbed for atomic charge-induced interactions and manipulations, and such subject has been studied in artificially deposited objects on thin insulating layers. We demonstrate that an entire layer of controllable atomic charges on a periodic lattice can be obtained by cleaving metallic Co1/3NbS2, an intercalated transition metal dichalcogenide. We identified a metastable charge state of Co with a different valence and manipulated atomic charges to form a linear chain of the metastable charge state. Density functional theory investigation reveals that the charge state is stable due to a modified crystal field at the surface despite the coupling between NbS2 and Co via a1g orbitals. The idea can be generalized to other combinations of intercalants and base matrices, suggesting that they can be a new platform to explore single-atom-operational 2D electronics/spintronics.

Study on the luminescence and energy level of lanthanide ions in Lu(0.8)Sc(0.2)BO3 host.

Emission and excitation spectra of undoped and Ln(3+) (Ln = Ce, Pr, Nd, Yb)-doped Lu(0.8)Sc(0.2)BO(3) were studied by vacuum ultraviolet spectroscopy, and the X-ray excited luminescence spectra were measured as well at room temperature. The undoped specimen presented two different emissions upon excitation at energies in the vicinity of the band gap or with X-ray. The emission at the highest energy side, located at 4.77 eV, was ascribed to self-trapped exciton, which is anchored by electron capture around the Sc site. We also observed three broad emission bands at 4.43, 3.02, and 2.10 eV, which might be attributed to the trapped exciton, defect -related emissions, or both. Energy transfer processes to the doped lanthanide ions in Lu(0.8)Sc(0.2)BO(3) via exciton state or sequential electron-hole capture are discussed. Finally, the energy level diagram for divalent and trivalent lanthanides in Lu(0.8)Sc(0.2)BO(3) was constructed using the obtained spectroscopic parameters and the three parameters method (Dorenbos, P. J. Phys.: Condens. Matter 2003, 15, 8417).