Semiconductor nanowires coupled to a superconductor provide a powerful testbed for quantum device physics such as Majorana zero modes and gate-tunable hybrid qubits.The performance of these quantum devices heavily relies on the quality of the induced superconducting gap.A hard gap,evident as vanishing subgap conductance in tunneling spectroscopy,is both necessary and desired.A hard gap has been achieved and extensively studied before in Ⅲ-Ⅴ semiconductor nanowires(InAs and InSb).In this study,we present the observation of a hard superconducting gap in PbTe nanowires coupled to a superconductor Pb.The gap size Δ is～1 meV(maximally 1.3meV in one device).Additionally,subgap Andreev bound states can also be created and controlled through gate tuning.Tuning a device into the open regime can reveal Andreev enhancement of the subgap conductance.These results pave the way for diverse superconducting quantum devices based on PbTe nanowires.
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