Niobium-based dichalcogenides $({\mathrm{NbX}}_2, \text{where} \mathrm{X}=\mathrm{S}, \mathrm{Se}, \mathrm{Te})$ exhibit tunable intertwining charge density waves (CDWs) and superconductivity, especially ${\mathrm{NbSe}}_2$ and ${\mathrm{NbTe}}_2$, which have attracted much attention due to their abundant electronic properties. However, the evolution of CDWs and superconductivity from ${\mathrm{NbSe}}_2$ to ${\mathrm{NbTe}}_2$ remains elusive. Here, using ultralow temperature scanning tunneling microscopy and spectroscopy (STM/STS) at 400 mK, we discover local short-range CDW patterns in 1T-NbSeTe, in which the three CDW components are spatially decoupled, indicating that the CDW in 1T-NbSeTe resides in a melted state of the 3 × 3 CDW of $2\mathrm{H}\text{−}{\mathrm{NbSe}}_2$ and 3 × 1 CDW orders of $1{\mathrm{T}}^{″}\text{−}{\mathrm{NbTe}}_2$. The short-range CDWs coexist with the superconductivity below a critical temperature of ∼1.5 K and an upper critical field of ∼1.7 T. The scaling relationship between the zero-energy density of states and the superconducting gap across a single vortex indicates that 1T-NbSeTe is a dirty superconductor. These findings provide valuable insights into the doping induced CDW melting and superconducting states in transition metal dichalcogenides.

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• Charge density waves
• Density of states
• Impurities in superconductors
• Superconducting gap
• Vortices in superconductors
• Low-temperature superconductors
• Transition metal dichalcogenides
• BCS theory
• Scanning tunneling microscopy
• Scanning tunneling spectroscopy