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Linear resistivity-temperature ( R - T ) at low temperatures, referred to as strange metal (SM), is an unusual characteristic observed in strongly correlated systems. SM is often mingled with superconductivity and magnetism in various materials. Here, we report a linear R - T relation in a hole-doped, degenerate spin-valley (SV) semiconductor, V 0.25 W 0.75 Se 2 , with hole pockets in the valence band. SM emerges over a wide temperature range (1.8-150 K) without any apparent superconductivity down to 110 mK. This SM behavior is suppressed at low temperatures below 20 K in the presence of a magnetic field. The ansatz R ( H , T ) - R ( 0 , 0 ) ∝ ( α k B T ) 2 + ( γ μ B μ 0 H ) 2 yields the γ/α ratio of ∼4, larger than the previous reports. The observed SM over a wide temperature range is explained by a spin-orbit coupling (SOC)-mediated SV pair with strong correlation effects, analogous to a phonon-mediated Cooper pair in superconductivity. This finding opens possible routes for understanding strange metal behavior through the interplay of strong SOC and strong Coulomb interactions.

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs), such as tungsten diselenide (WSe 2 ), hold immense potential for applications in electronic and optoelectronic devices. However, a significant Schottky barrier height (SBH) at the metal-semiconductor (MS) interface reduces the electronic device performance. Here, we present a unique 2D/2D contact method for minimizing contact resistance and reducing the SBH. This approach utilizes vanadium-doped WSe 2 (V-WSe 2 ) as the drain and source contacts. The fabricated transistor exhibited a stable operation with p-type quasi-ohmic contact and a high on/off current ratio surpassing 10 8 at room temperature, reaching 10 11 at 10 K. The device achieved an on-current of 68.87 μA, a high mobility of 103.80 cm 2 V -1 s -1 , a low contact resistance of 0.92 kΩ, and remarkably low SBH values of 1.51 meV for holes at V GS = -120 V with fixed V DS = 1 V. Furthermore, a Schottky photodiode has been fabricated, utilizing V-WSe 2 and Cr as the asymmetric contact platform, showing a responsivity of 116 mA W 1- . The findings of this study suggest a simple and efficient method for improving the performance of TMDC-based transistors.

Although magnetic order is suppressed by a strong frustration, it appears in complex forms such as a cycloid or spin density wave in weakly frustrated systems. Herein, we report a weakly magnetically frustrated two-dimensional (2D) van der Waals material CrPSe 3 . Polycrystalline CrPSe 3 was synthesized at an optimized temperature of 700 °C to avoid the formation of any secondary phases (e.g., Cr 2 Se 3 ). The antiferromagnetic transition appeared at T N ≈ 127 K with a large Curie-Weiss temperature θ CW ≈ -301 K via magnetic susceptibility measurements, indicating weak frustration in CrPSe 3 with a frustration factor of f (|θ CW |/ T N ) ≈ 2.4. Evidently, the formation of a long-range incommensurate antiferromagnetic order was revealed by neutron diffraction measurements at low temperatures (below 120 K). The monoclinic crystal structure of the C 2/ m symmetry is preserved over the studied temperature range down to 20 K, as confirmed by Raman spectroscopy measurements. Our findings on the incommensurate antiferromagnetic order in 2D magnetic materials, not previously observed in the MPX 3 family, are expected to enrich the physics of magnetism at the 2D limit, thereby opening opportunities for their practical applications in spintronics and quantum devices.