Impedance Enhanced Nonlinearity in Titanium Nitride Quantum Circuits

The high kinetic inductance offered by titanium nitride has seen recent attention for use in linear inductors for superconducting qubits, parametric amplifiers, superconducting detectors and for strong coupling in hybrid systems. While typical applications focus on ultra-high impedance devices exceeding the resistance quantum, we explore the opposite end of the spectrum in search of a nonlinear system with higher operating temperature limits and power limits than a conventional Josephson Junction. Utilizing fractal geometries together with nanowire inductors, we combine reduced critical currents with increased zero point current fluctuations to enhance the strength of the intrinsic Kerr nonlinearity. We demonstrate self-Kerr strengths exceeding 1% of the device line-width, realizing a novel path to an interesting parameter space for quantum devices.