Pressure-induced coherent sliding-layer transition in the excitonic insulator Ta2NiSe5

Nakano, A.; Sugawara, K.; Tamura, S.; Katayama, N.; Matsubayashi, K.; Okada, T.; Uwatoko, Y.; Munakata, K.; Nakao, A.; Sagayama, H.; Kumai, R.; Sugimoto, K.; Maejima, N.; Machida, A.; Watanuki, T.; Sawa, H.

doi:10.1107/S2052252517018334

Figure 3
(a) The in-plane crystal structure viewed from the b axis (common to phases below and above 3 GPa). (b) and (c) The crystal structure of the phases below 3 GPa viewed from (b) the a axis and (c) the c axis. (d) and (e) The crystal structure obtained above 3 GPa viewed from (d) the a axis and (e) the c axis. The dotted blue lines indicate the unit cell for each structure at the given pressure, while α and d indicate the Se—Ni—Se bond angle and the layer thickness, respectively. The dashed green lines represent the Se(2)–Se(3) distance (see also Fig. 5