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Three-dimensional Dirac semimetal Cd3As2, hosting a pair of Dirac cones and Fermi-arc-like surface states, displays numerous exotic properties in transport experiments. Particularly, when proximitized with superconductors, Cd3As2 is expected to realize topological superconductivity and Majorana zero modes, which are elemental for fault-tolerant quantum computing. Implementing electronic transport measurements on superconductor Al-Cd3As2 nanoplate-Al heterostructures, here we investigate the effect of gate modulation and magnetic field on superconducting properties of Cd3As2. A proximity-induced superconducting state is well achieved in the junction which can be effectively tuned by gate voltage. The critical current oscillations under out-of-plane magnetic fields are well fitted with the Fraunhofer function. The critical supercurrent shows a slower decay as the gate voltage is tuned to negative under in-plane magnetic fields, which may arise from the enhanced contribution of surface states. An anisotropic superconductivity is also observed when in-plane rotating magnetic fields. Our results report the gate modulation of supercurrents in different magnetic field directions, which should be valuable for further exploring the topological superconductivity in Dirac semimetals.

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Topological semimetals are exotic phases of quantum matter with gapless electronic excitation protected by symmetry. Benefitting from its unique relativistic band dispersion, topological semimetals host abundant quantum states and quantum effects, esuch as Fermi-arc surface states and chiral anomaly. In recent years, due to the potential application in topological quantum computing, the hybrid system of topology and superconductivity has aroused wide interest in the community. Recent experimental progress of topological semimetal-superconductor heterojunctions is reviewed in two aspects: 1) Josephson current as a mode filter of different topological quantum states; 2) detection and manipulation of topological superconductivity and Majorana zero modes. For the former, utilizing Josephson interference, ballistic transport of Fermi-arc surface states is revealed, higher-order topological phases are discovered, and finite-momentum Cooper pairing and superconducting diode effect are realized. For the latter, by detecting a.c. Josephson effect in Dirac semimetal, the 4π-periodic supercurrent is discovered. By all-electric gate control, the topological transition of superconductivity is obtained. Outlooks of future research on topological semimetal-superconductor heterojunctions and their application in Majorana braiding and topological quantum computing are discussed.

Dirac semimetals are promising materials for broadband and fast photodetection due to their gapless nature. Dirac heterostructures consisting of 2D Dirac semimetal graphene and its 3D analogue Cd3As2 should take the ascendency of high carrier mobility in both materials, while overcome the limitation of weak optical absorption in graphene-based devices and suppress the dark current occurring in pure Cd3As2 photodetectors. Herein, we report high-performance photodetectors based on a 3D Dirac semimetal Cd3As2/monolayer graphene heterostructure, which show broadband photoresponse from visible (488 nm) to mid-infrared (10 μm) wavelength region at room temperature without an external bias. The photodetectors are with a maximum responsivity of 0.34 mA/W at 488 nm and a fast response speed of ∼13 μs. In addition, the photoresponse can be enhanced by a gate voltage even in a long wavelength region. Our work suggests that the combination of the graphene and 3D Dirac semimetal is promising for high-performance photodetectors with broadband detection, high sensitivity, and rapid response.