The thermal response of proximity Josephson junctions (JJs) is governed by the temperature ($T$)-dependent occupation of Andreev bound states (ABS), making them promising candidates for sensitive thermal detection. In this study, we systematically engineer ABS to enhance the thermal sensitivity of critical current ($I_{\mathrm{c}}$) of proximity JJs, quantified as $|d{I}_{\mathrm{c}}/dT|$ for the threshold readout scheme and $|d{I}_{\mathrm{c}}/dT·I_{\mathrm{c}}^{-1}|$ for the inductive readout scheme. Using a gate-tunable graphene-based JJ platform, we explore the impact of key parameters—including channel length, transparency, carrier density, and superconducting material—on the thermal response. Our results reveal that the proximity-induced superconducting gap plays a crucial role in optimizing thermal sensitivity. For the threshold scheme, we obtain a width-normalized sensitivity of $|d{J}_{\mathrm{c}}/dT|\approx 0.2\mathrm{\mu }\mathrm{A}{\mathrm{K}}^{-1}\mathrm{\mu }{\mathrm{m}}^{-1}$ at 0.1 K in an aluminum-based graphene JJ. Notably, we see a maximum $|d{I}_{\mathrm{c}}/dT·I_{\mathrm{c}}^{-1}|$ value of $0.6{\mathrm{K}}^{-1}$ at 50 mK with titanium-based graphene JJs. By demonstrating a systematic approach to engineering ABS in proximity JJs, this work establishes a versatile framework for optimizing thermal sensors and advancing the study of ABS-mediated transport.

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• Andreev bound states
• Quantum information with solid state qubits
• Quantum sensing
• Josephson junctions
• Superconducting devices
• Bolometers
• Calorimetry
• Thermometry