Fig. 4
From: Nonlinear magnetotransport shaped by Fermi surface topology and convexity
Theoretical nonlinear charge current and Fermi surface. a Calculated longitudinal second-order current density \(J_{bb}^{(2)}\) versus Fermi level µ for current flowing along the b axis with a Zeeman energy of 0.1 meV. b, c Calculated Fermi surfaces of bulk WTe2 at µ = 0 and 120 meV, respectively, with three horizontal cuts shown underneath. ‘e’ and ‘h’ indicates the electron and hole pocket, respectively. Based on the result of Fig. 2f, these two chemical potentials correspond to T = 0 K and 300 K, respectively. d Temperature dependence of the ratio \(- J_{ii}^{(2)}/\left[ {J_{ii}^{(1)}} \right]^2 \propto \chi\) for the current applied along the a and b axes. The T axis takes into account both the thermal broadening by the Fermi-Dirac distribution and the Fermi level shift. e, f Variation of the calculated \(J_{bb}^{(2)}\) at 300 K with magnetic field angle φ (e) and with the field intensity at φ = 90° (f). Dashed lines are, respectively, the function sin(φ) and a linear fit to the calculated points. The above results in a–f are calculated based on the Wannier Hamiltonian of bulk WTe2, which reproduces the density functional theory (DFT) band structure shown in Fig. 1b. g The calculated second-order current density \(J_{bb}^{(2)}\) versus the Fermi level µ for the simplified quasi-bulk tight-binding model. h, i The energy dispersion and Fermi surfaces at µ = 200 and 75 meV, respectively, which correspond to the values marked by the vertical dashed lines in g. Calculated currents are presented in arbitrary units in all panels (Supplementary Note 1)
