Fig. 2: Phase transitions as a function of temperature in NH4I.
From: Ultrasensitive barocaloric material for room-temperature solid-state refrigeration
a The contour plots of dynamic structure factor, S(Q,ω), for NH4I at 160, 260, and 300 K measured at PELICAN with Ei = 3.72 meV. b The contour plot of elastic structure factor S(Q) as a function of temperature. c Comparison of S(Q) at 160, 260, and 300 K. The Bragg peaks for the high-T α-phase and the intermediate-T β-phase are marked with subscripted ‘α’ and ‘β’, respectively. d Experimental mean-squared displacement, <u2>, determined from the fitting of S(Q) to S(Q) ∝ exp(−Q2〈u2〉/3) (see Supplementary Fig. 8). e Sliced S(Q,ω) over the Q range of [1.55, 1.65] Å−1 as a function of energy transfer.
