The metallic ground state in two-dimensional (2D) superconductors, characterized with saturated resistance when approaching absolute zero temperature, has attracted much attention but is still under intense scrutiny. Especially, the experimental measurements in ultralow temperature region are challenging for 2D superconductors due to the sensitivity to external perturbations. Here, we report electrical transport properties of 2D transition metal dichalcogenide (TMD) superconductor 4Ha-TaSe2 flakes. Ising superconductivity revealed by ultrahigh in-plane critical field (Bc2//) going beyond the Pauli paramagnetic limit (Bp) is detected in 4Ha-TaSe2, in which spins of the pairing electrons are strongly pinned by the effective Zeeman field even in bulk situation due to the weak coupling between the TaSe2 sub-monolayers. In perpendicular magnetic field, the resistance saturation state induced by external noise, named as "extrinsic anomalous metallic state", is observed in 2D TaSe2 flakes. However, with further decreasing temperature credible evidence of intrinsic anomalous metallic state is obtained by adequately filtering external radiation. Our work indicates that at ultralow temperatures the anomalous metallic state can be experimentally revealed in 2D crystalline TMD superconductors as the quantum ground state by precise measurement with high-attenuation low-pass filters.

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A new n-type phthalocyanine-based sensor is developed for ultrasensitive and highly selective detection of trace amounts of NO2 against NH3 and H2S.

The electrical transport properties of rare-earth tritelluride TbTe3 are investigated at low temperatures and high magnetic fields. The charge-density-wave and anti-ferromagnetic transition are found at 334 K (340 K) and 6.0 K (9.4 K) for bulk TbTe3 (thin device), respectively. An extremely large and non-saturating magnetoresistance (MR) as high as 5600% is detected under a perpendicular magnetic field at 1.8 K and 9 T. Furthermore, angular-dependent transport measurements reveal obvious anisotropic MR behaviors in both bulk TbTe3 and thin devices. Moreover, in the thin TbTe3 device, exotic linear MR at low temperatures is observed in all field directions. Hall measurements are also performed, and the quantitative fitting of the two-band model to longitudinal and Hall conductivity of the TbTe3 device reveals two types of carriers (hole and electron). Our work may stimulate interests of layered rare-earth tritellurides in fundamental physics and potential technological applications.