Fig. 3: Electronic Lifshitz transition in Ta2Ni(Se,S)5.
From: Anomalous excitonic phase diagram in band-gap-tuned Ta2Ni(Se,S)5
ARPES spectra along X − Γ − X direction for samples with different S-doping levels. a High-temperature orthorhombic phase. b Low-temperature monoclinic phase (except for 100% S-doping, where no structural transition was evidenced down to 10 K). Spectra from linear horizontal (LH, blue) and linear vertical (LV, red) polarization of incident light are overlaid, highlighting Ta 5\({d}_{{x}^{2}-{y}^{2}}\) conduction band and Ni 3dxy valence bands respectively. VBT - valence band top. c DFT calculation of 22% S-doped compound in high-temperature orthorhombic phase, and the evolution of Eg extracted from DFT calculation and photoemission spectra as a function of S-doping. d DFT calculation of 22% S-doped compound in low-temperature monoclinic phase, and the evolution of 2kF extracted from DFT calculation and photoemission spectra as a function of S-doping. Error bars are determined based on (c) the variation between dispersion fitting models and (d) the fitting error of the MDC peak position.
