Ta2NiSe7 is a quasi-one-dimensional (quasi-1D) transition-metal chalcogenide with Ta and Ni chain structures. An incommensurate charge-density wave (CDW) in this quasi-1D structure was well studied previously using tunnelling spectrum, X-ray, and electron diffraction, whereas its transport property and the relation to the underlying electronic states remain to be explored. Here, we report our results of the magnetoresistance (MR) on Ta2NiSe7. A breakdown of Kohler's rule is found upon entering the CDW state. Concomitantly, a clear change in curvature in the field dependence of MR is observed. We show that the curvature change is well described by the two-band orbital MR, with the hole density being strongly suppressed in the CDW state, indicating that the p orbitals from Se atoms dominate the change in transport through CDW transition.

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The behavior of charge density wave (CDW) in an external magnetic field is dictated by both orbital and Pauli (Zeeman) effects. A quasi-one-dimensional (Q1D) system features Q1D Fermi surfaces that allow these effects to be distinguished, which in turn can provide sensitive probe to the underlying electronic states. Here we studied the field dependence of an incommensurate CDW in a transition-metal chalcogenide Ta2NiSe7 with a Q1D chain structure. The angle-dependent magnetoresistance (MR) is found to be very sensitive to the relative orientation between the magnetic field and the chain direction. With an applied current fixed along the b axis (the chain direction), the angle-dependent MR shows a striking change of the symmetry below TCDW only for a rotating magnetic field in the ac plane. In contrast, the symmetry axis remains unchanged for other configurations (H in ab and bc plane). The orbital effect conforms to the lattice symmetry, while Pauli effect in the form of can be responsible for such symmetry change, provided that the Fermi velocity is significantly anisotropic and the nesting vector changes in a magnetic field, which is corroborated by our first-principles calculations. Our results show that the angle-dependent MR is a sensitive transport probe of CDW and can be useful for the study of low-dimensional systems in general.Condensed matter systems with low dimensionality have demonstrated great potential by hosting rich and exotic physics 1,2 which allows an alternative and fascinating route for exploring exotic phenomena,

We demonstrate real-time 24-Tb/s dense wavelength division multiplexing (DWDM) transmission over a 1910-km field-deployed G.654.E fiber link using 24 in-line wide-bandwidth Erbium-doped fiber amplifiers with a widened bandwidth of 6 THz in the cost-effective C-band. The DWDM system consists of 60 100-GHz-spaced 400-Gb/s wavelength channels, modulated with probabilistic constellation shaped polarization-division-multiplexed 16-point quadrature-amplitude modulation and fast-than-Nyquist shaping. This field trial shows the feasibility of achieving a record per-fiber capacity of 24 Tb/s in field-deployed 2000-km-class terrestrial fiber links by using the widened C-band.

The strange-metal state is a crucial problem in condensed matter physics highlighted by its ubiquity in almost all major correlated systems 1-7 . Its understanding could provide important insight into high-Tc superconductivity 2 and quantum criticality 8 . However, with the Fermi liquid theory failing in strange metals, understanding the highly unconventional behaviors has been a long-standing challenge. Fundamental aspects of strange metals remain elusive, including the nature of their charge carriers 1 . Here, we report the observation of a giant Nernst response in the strange-metal state in a two-dimensional superconductor 2M-WS2. A giant Nernst coefficient comparable to the vortex Nernst signal in superconducting