Dark vertical conduction of cavity-embedded semiconductor heterostructures*

We present a linear-response theory for the electronic transport along the growth direction of an arbitrary semiconductor heterostructure coupled to a photonic resonator in its vacuum state (no real photons are injected or created). To ensure a coupling between intersubband and photonic excitations, the cavity field is assumed to be polarized along the growth direction. We point out how the light-matter and electron-electron interactions hybridize the (confined) many-body ground state with the continuum, showing how this can affect the conduction properties in the growth direction. Our findings are relevant, for instance, in the development of cavity-embedded quantum-well infrared photodetectors (QWIP).