Massive Dirac-Pauli physics in lead-halide perovskites

TL;DR

This paper reveals the presence of Dirac-Pauli physics in lead-halide perovskites, showing how the Pauli term influences quantum phenomena and enabling tabletop simulations of analogue Dirac-Pauli equations.

Contribution

It demonstrates the natural emergence of the Pauli term in lead-halide perovskites and explores its measurable effects on bound states, scattering, and spin phenomena.

Findings

Decreased electron binding energy near charged defects due to polarizability and Darwin-like term

Altered exciton states caused by strong spin-orbit coupling from the Pauli term

Spin polarization in scattered electrons from asymmetric potential barriers

Abstract

In standard quantum electrodynamics (QED), the so-called non-minimal (Pauli) coupling is suppressed for elementary particles and has no physical implications. Here, we show that the Pauli term naturally appears in a known family of Dirac materials -- the lead-halide perovskites, suggesting a novel playground for the study of analogue QED effects. We outline measurable manifestations of the Pauli term in the phenomena pertaining to (i) relativistic corrections to bound states (ii) the Klein paradox, and (iii) spin effects in scattering. In particular, we demonstrate that (a) the binding energy of an electron in the vicinity of a positively charged defect is noticeably decreased due to the polarizability of lead ions and the appearance of a Darwin-like term, (b) strong spin-orbit coupling due to the Pauli term affects the exciton states, and (c) scattering of an electron off an energy barrier with broken mirror symmetry produces spin polarization in the outgoing current. Our study adds to understanding of quantum phenomena in lead-halide perovskites, and paves the way for tabletop simulations of analogue Dirac-Pauli equations.