Figure 3. Temperature-induced Lifshitz transition in ZrTe₅.

(a) Fermi surface evolution with temperature when ZrTe₅ is cooled down from 255 to 35 K. (b) Corresponding constant energy contour evolution with temperature at a binding energy of 100 meV. (c,d) Momentum distribution curves (MDCs) at the Fermi level (E_F) measured along the vertical momentum cut (Γ–Y direction) as indicated in the 35 K panel of a at different temperatures (open circles). To improve data statistics, the MDCs are obtained by integrating within ±5 meV energy window with respect to the Fermi level. Because multiple-peak features are not resolved, we fitted the MDCs by a Gaussian to estimate the pocket size and signal intensity. The fitted MDC width and spectral weight are shown in g,h, respectively. (e,f) MDCs at a binding energy of 100 meV measured along the horizontal momentum cut (Γ–X direction) as indicated in the 35 K panel of b at different temperatures (open circles). The MDCs are obtained by integrating within ±5 meV energy window at the binding energy of 100 meV. Here the MDCs show two clear peaks that are approximated by two Lorentzians or Gaussians. The distance between the two peaks is shown in i that is related to the area of the constant energy contours in b. (g) Temperature dependence of the MDC width (full-width at half-maximum) extracted from c,d. (h) Temperature dependence of the MDC weight, the integrated area of MDCs, extracted from c,d. (i) Temperature dependence of the two-peak distance of MDCs in e,f. (j) Temperature dependence of the lattice constant b with the measured data (black diamonds) replotted from ref. 62 and the fitted line (black line). The lattice constant b is related to the interlayer spacing.