Fig. 2: Semiparametric Bayesian modeling of the gapped Dirac-cone surface state.
From: Unveiling quasiparticle dynamics of topological insulators through Bayesian modelling
a Angle-resolved photoemission spectroscopy (ARPES) intensity plot in the vicinity of the Fermi level EF around the Γ point for TlBi(S0.2Se0.8)2 measured at T = 30 K with the Xe-Iα line (hν = 8.437 eV)14. b, c Schematic energy dispersion of gapless and gapped Dirac-cone bands, respectively. The full energy gap is 2Δ. Analytical form of the bare-band dispersion Es(k) used in the model is also shown at the bottom; s, ωDP, α, γ, Δ are branch index [upper (s = +1) or lower (s = −1) Dirac cone], Dirac-point energy, parabolic dispersion term, Dirac velocity, and Dirac gap, respectively. d Example of simulated ARPES intensity I(k, ω) used in the semiparametric Bayesian analysis, which is composed of photoelectron matrix-element term for the surface band Ms(k), single-particle spectral function As(k, ω), photoelectron matrix-element term for the background MB(k) and angle-integrated-type background B(ω). F(ω) denotes the Fermi–Dirac distribution function.
