Mixed-valence insulators with neutral Fermi surfaces.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29720630.
- Also identified by DOI 10.1038/s41467-018-04163-2 and PMC identifier 5932084.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Samarium hexaboride is a classic three-dimensional mixed valence system with a high-temperature metallic phase that evolves into a paramagnetic charge insulator below 40 K. A number of recent experiments have suggested the possibility that the low-temperature insulating bulk hosts electrically neutral gapless fermionic excitations. Here we show that a possible ground state of strongly correlated mixed valence insulators-a composite exciton Fermi liquid-hosts a three dimensional Fermi surface of a neutral fermion, that we name the "composite exciton." We describe the mechanism responsible for the formation of such excitons, discuss the phenomenology of the composite exciton Fermi liquids and make comparison to experiments in SmB<sub>6</sub>.