Uncovering the phonon spectra and lattice dynamics of plastically deformable InSe van der Waals crystals.

Stacking two-dimensional (2D) van der Waals (vdW) materials in a layered bulk structure provides an appealing platform for the emergence of exotic physical properties. As a vdW crystal with exceptional plasticity, InSe offers the opportunity to explore various effects arising from the coupling of its peculiar mechanical behaviors and other physical properties. Here, we employ neutron scattering techniques to investigate the correlations of plastic interlayer slip, lattice anharmonicity, and thermal transport in InSe crystals.

Phonon-Related Monochromatic THz Radiation and its Magneto-Modulation in 2D Ferromagnetic Cr Ge Te.

Searching multiple types of terahertz (THz) irradiation source is crucial for the THz technology. In addition to the conventional fermionic cases, bosonic quasi-/particles also promise energy-efficient THz wave emission. Here, by utilizing a 2D ferromagnetic Cr Ge Te crystal, first a phonon-related magneto-tunable monochromatic THz irradiation source is demonstrated.

Field-induced quantum spin disordered state in spin-1/2 honeycomb magnet NaCoTeO.

Spin-orbit coupled honeycomb magnets with the Kitaev interaction have received a lot of attention due to their potential of hosting exotic quantum states including quantum spin liquids. Thus far, the most studied Kitaev systems are 4d/5d-based honeycomb magnets. Recent theoretical studies predicted that 3d-based honeycomb magnets, including NaCoTeO (NCTO), could also be a potential Kitaev system.

Antiferromagnetic Kitaev interaction in1/2 cobalt honeycomb materials NaCoSbOand NaCoTeO.

Finding new materials with antiferromagnetic (AFM) Kitaev interaction is an urgent issue for quantum magnetism research. We conclude that NaCoSbOand NaCoTeOare new honeycomb cobalt-based systems with AFM Kitaev interaction by carrying out inelastic neutron scattering experiments and subsequent analysis. The spin-orbit excitons observed at 20-28 meV in both compounds strongly support the idea that Coions of both compounds have a spin-orbital entangled= 1/2 state.

Atomic scale electronic structure of the ferromagnetic semiconductor CrGeTe.

CrGeTe is an intrinsic ferromagnetic semiconductor with van der Waals type layered structure, thus represents a promising material for novel electronic and spintronic devices. Here we combine scanning tunneling microscopy and first-principles calculations to investigate the electronic structure of CrGeTe. Tunneling spectroscopy reveals a surprising large energy level shift and change of energy gap size across the ferromagnetic to paramagnetic phase transition, as well as a peculiar double-peak electronic state on the Cr-site defect.