Antiparticle of exciton in semimetals
arXiv:2203.17038 · doi:10.1103/PhysRevB.106.235145
Abstract
An emergent quantized field enriches quantum many-body systems. We propose an antiparticle analog of the exciton in semimetals as an emergent collective mode in interacting electron systems. We show that inter-band excitations in semimetals are generally comprised of both excitons and antiparticles of excitons. These two stand for two distinct inter-band collective modes in semimetals, having different energies and opposite conserved charges. The conserved charge here is a quantity conjugate to a joint U(1) symmetry of two electron's bands associated with the inter-band excitations. The opposite charges foster fertile scattering processes among the inter-band collective modes. In spin-polarized systems, they also suggest possible experimental detections of the antiparticles. We clarify that the effective theory of the inter-band excitations is given by a generalized Klein-Gordon theory. Our theory provides a comprehensive understanding of excitonic spectra in generic semimetals, bringing a new insight into electronic collective phenomena in solids.
23 pages. We explain physical difference between antiexciton proposed in this paper and those in previous works on excitons in semiconductors
References in corpus (6)
- Amplitude / Higgs Modes in Condensed Matter Physics
- Models of coherent exciton condensation
- Multicomponent electron-hole superfluidity and the BCS-BEC crossover in double bilayer graphene
- Probing the semiconductor to semimetal transition in InAs/GaSb double quantum wells by magneto-infrared spectroscopy
- Resistive signature of excitonic coupling in an electron-hole double layer with a middle barrier
- Dissipationless Spin-Charge Conversion in Excitonic Pseudospin Superfluid