Dirac fermions and flat bands in the ideal kagome metal FeSn.
Mingu KangLinda YeShiang FangJhih-Shih YouAbe LevitanMinyong HanJorge I FacioChristopher JozwiakAaron BostwickEli RotenbergMun K ChanRoss D McDonaldDavid E GrafKonstantine KaznatcheevElio VescovoDavid C BellEfthimios KaxirasJeroen van den BrinkManuel RichterMadhav Prasad GhimireJoseph G CheckelskyRiccardo CominPublished in: Nature materials (2019)
A kagome lattice of 3d transition metal ions is a versatile platform for correlated topological phases hosting symmetry-protected electronic excitations and magnetic ground states. However, the paradigmatic states of the idealized two-dimensional kagome lattice-Dirac fermions and flat bands-have not been simultaneously observed. Here, we use angle-resolved photoemission spectroscopy and de Haas-van Alphen quantum oscillations to reveal coexisting surface and bulk Dirac fermions as well as flat bands in the antiferromagnetic kagome metal FeSn, which has spatially decoupled kagome planes. Our band structure calculations and matrix element simulations demonstrate that the bulk Dirac bands arise from in-plane localized Fe-3d orbitals, and evidence that the coexisting Dirac surface state realizes a rare example of fully spin-polarized two-dimensional Dirac fermions due to spin-layer locking in FeSn. The prospect to harness these prototypical excitations in a kagome lattice is a frontier of great promise at the confluence of topology, magnetism and strongly correlated physics.
Keyphrases
- density functional theory
- transition metal
- molecular dynamics
- single molecule
- high resolution
- room temperature
- monte carlo
- gene expression
- genome wide
- machine learning
- molecular dynamics simulations
- high throughput
- big data
- single cell
- current status
- mass spectrometry
- artificial intelligence
- tandem mass spectrometry