Pressure-Induced Large Volume Collapse, Plane-to-Chain, Insulator to Metal Transition in CaMnBi.

In situ high pressure single crystal X-ray diffraction study reveals that the quantum material CaMnBi undergoes a unique plane to chain structural transition between 2 and 3 GPa, accompanied by a large volume collapse. Puckered Mn-Mn honeycomb layer converts to quasi-one-dimensional (1D) zigzag chains above the phase transition pressure. Single crystal measurements reveal that the pressure-induced structural transformation is accompanied by a dramatic 2 orders of magnitude drop of resistivity.