Fig. 3

Evolution of the Yb 4f states and crystal field effects in YbAl₃. a Evolution of the Kondo resonance peak with temperature, from integrating EDCs over k region highlighted as red in d. b Change in the chemical potential (Δμ) and in the 4f quasiparticle scattering rate with temperature. Δμ is estimated from the shift in binding energy of the 4f-derived heavy band (blue) and the band bottom of the light electron-like pocket at (0, 0) (red) relative to 255 K. Error bars represent uncertainty due to statistical error of one standard deviation from the fitting process. c Temperature dependence of the integrated spectral weight (0–0.2 eV) of the 4f states which show a ln(T ₀/T) behavior above T ^* = 37 K. Error bars represent 3% margin of error. d High resolution E vs. k plot along (0, 0)–(0, π) at 21 K showing dispersive crystal electric field (CEF) split states. Extracted dispersions of the three different CEF split states (shown in blue, pink and green) are superimposed on the image plot. In addition to statistical error of one standard deviation from the fitting process, error bars in d, also include variability in the fit results by holding one and/or two peak positions constant in the multi-peak fitting process