STM study of tip-pulse induced non-equilibrium phases in 1T/2H-NbSe₂ heterostructures

By applying STM voltage pulses, we induce the formation of single-layer 1T-NbSe₂ with a non-equilibrium charge-density-wave (CDW) state on 2H-NbSe₂ single crystals. We identify distinct types of 1T domains, characterized by unique Star-of-David (SOD) configurations and interlayer stacking geometries. STS measurements reveal that isolated SODs can serve as nucleation centers for the Mott-insulating phase. DFT+U calculations further show that interlayer stacking has a pronounced effect on the magnetic moments of SODs. These stacking-dependent local moments act as pair breakers, locally suppressing superconductivity in the underlying 2H-NbSe₂. Moreover, we observe a "jamming" phase, where the SOD density exceeds that of conventional 1T-NbSe₂. The pronounced suppression of superconducting gap in this jamming phase indicates the emergence of ferromagnetism. Our findings demonstrate the complex interplay among Mottness, CDW, localized magnetism, and superconductivity in 1T/2H-NbSe₂ heterostructures.