We report a study of the structural phase transitions induced by pressure in bulk black phosphorus by using both synchrotron x-ray diffraction for pressures up to 12.2 GPa and Raman spectroscopy up to 18.2 GPa. Very recently black phosphorus attracted large attention because of the unique properties of few-layers samples (phosphorene), but some basic questions are still open in the case of the bulk system. As concerning the presence of a Raman spectrum above 10 GPa, which should not be observed in an elemental simple cubic system, we propose a new explanation by attributing a key role to the non-hydrostatic conditions occurring in Raman experiments. Finally, a combined analysis of Raman and XRD data allowed us to obtain quantitative information on presence and extent of coexistences between different structural phases from ∼5 up to ∼15 GPa. This information can have an important role in theoretical studies on pressure-induced structural and electronic phase transitions in black phosphorus.
Coexistence of pressure-induced structural phases in bulk black phosphorus: A combined x-ray diffraction and Raman study up to 18 GPa / Joseph, B.; Caramazza, S.; Capitani, F.; Clarte, T.; Ripanti, F.; Lotti, P.; Lausi, A.; Di Castro, D.; Postorino, P.; Dore, P.. - In: JOURNAL OF PHYSICS. CONDENSED MATTER. - ISSN 0953-8984. - 30:49(2018), p. 494002. [10.1088/1361-648X/aaebe5]