Fig. 2. Pressure dependence of lattice parameters of DTN, as measured by neutron diffraction.

a Pressure dependence of the lattice parameter a. b Pressure dependence of the lattice parameter c. Open and closed symbols correspond to 300 and 1.8 K data, respectively. Dotted lines denote the irreversible structural phase transition at P_irr ~ 6 kbar. Red lines are fit results (see text for details).