Geometric Suppression in the Photoelectric Effect: Completing Our Understanding Through Orbital Angular Momentum

The photoelectric effect has been studied almost exclusively using light with zero orbital angular momentum (OAM) since Einstein's foundational explanation in 1905. We predict that the photoelectric current from OAM-carrying light exhibits a fundamental power-law suppression, I (ℓ) ∝ ℓ^ (−α) with α ≈ 1 to 3, resulting in orders-of-magnitude reduction in quantum yield even when the beam is fully contained within the photocathode area. This suppression originates from two coupled quantum mechanisms: (1) intra-wavefunction interference caused by the azimuthal phase gradient exp (iℓϕ), which induces destructive interference within the electronic phase-coherence length; and (2) angular momentum conservation constraints, where a centrifugal energy barrier energetically forbids direct OAM transfer to the photoelectron for ℓ ≥ 1, forcing bottlenecked transfer to the crystal lattice via chiral phonons. We propose experimental verification using a K₂CsSb photocathode and a commercial spatial light modulator, measuring absolute photoelectric yield as a function of OAM quantum number ℓ from 1 to 200. This identifies a previously unrecognised geometric dimension of the photoelectric effect and offers a new spectroscopic probe for electronic coherence and electron-phonon dynamics in condensed matter.