High-energy quasiparticle injection into mesoscopic superconductors

At non-zero temperatures, superconductors contain excitations known as Bogoliubov quasiparticles (QPs). The mesoscopic dynamics of QPs inform the design quantum information processors, among other devices. Knowledge these stems from experiments in which are injected a controlled fashion, typically at energies comparable to pairing energy1–5. Here we perform tunnel spectroscopy superconductor under high electric fields. We observe QP injection due field-emitted electrons with 106 times energy, an unexplored regime dynamics. Upon application gate voltage, decreases critical current and, sufficiently field, field-emission (<0.1 nA our device) switches into normal state, consistent earlier observations6. expect that high-energy will be useful for developing QP-tolerant allow rapid control resonator quality factors and enable electric-field-controlled superconducting devices new functionality. Typically, energy order gain insights quasiparticle Tunnelling field now provides where impinge energy.