Fig. 2: Temperature dependence of the spin gap in TbMn6Sn6.
From: Orbital character of the spin-reorientation transition in TbMn6Sn6
a The evolution of the acoustic mode intralayer spin wave dispersion along q = (H, 0, 2) at T = 100, 150, 200, 240, 300, and 350 K through the spin-reorientation (SR) transition at TSR = 310 K. The dashed line at T = 100 K corresponds to the ground state dispersion as obtained from fits to the Heisenberg model described in Ref. 24. b The inelastic neutron scattering spectra at (0,0,2) are plotted as χ″(q, E)/E for several temperatures up to (solid lines) and above TSR (dashed lines). c INS spectra at (1,0,2) for several temperatures. d The temperature dependence of the spin gap energy at (0, 0, 2) and (1, 0, 2) as obtained from the maxima in panels b and c. The dashed lines in d correspond to random-phase approximation (RPA) calculations in the uniaxial phase. Observation of dynamical features in the hashed area are obscured by the instrumental elastic resolution. Error bars are statistical in origin and represent one standard deviation.
