Anomalous dissipation in KTaO$_3$ (111) interface superconductor in the absence of external magnetic field

Understanding the nature of dissipation mechanisms in two-dimensional (2D) superconductors under applied perpendicular magnetic field ($B$$_\perp$) using very small current ($I$) excitations has been a subject of huge interest in the last two decades. However, dissipation mechanisms at large $I$ drive remain largely unexplored. We investigate this fundamental question for a newly fabricated KTaO$_3$ (111)-based interfacial superconductor, which lies in the intermediate disorder regime. We demonstrate two distinct regimes of dissipation across the Berezinskii Kosterlitz Thouless phase transition temperature ($T_\mathrm{BKT}$). Below $T_\mathrm{BKT}$, $I$ driven breaking of vortex-antivortex pairs and superconducting weak links are found to be the major sources of dissipation. Most importantly, we uncover a new source of dissipation arising from large electric field driven electronic instability in the temperature range $T_\mathrm{BKT}$ < $T$ < $T_C$ (where $T_C$ is superconducting transition temperature), leading to a rare observation of clockwise hysteresis loop in $I$-$V$ curve. While such behavior had been reported earlier in type II superconductors in the presence of $B$$_\perp$, experimental demonstration in the absence of external $B$ remains elusive so far. Our results not only reveal the microscopic structure of 2D superconductors close to BKT transition, but also deepens the understanding of how a BKT system is ultimately transferred to a normal state by increasing $I$.