Emergent Magnetic Phases in Pressure-Tuned van der Waals Antiferromagnet FePS3

Raman and first-principles study of the pressure-induced Mott-insulator to metal transition in bulk FePS3

“…The carrier drift velocity and thermal performance of these high-pressure phases are affected by phonon renormalization, which can be analyzed in a non-invasive manner by using Raman spectroscopy. Furthermore, according to recent neutron-scattering measurements [34], the low pressure (LP) phase and the first high pressure (HP-I) phase of bulk FePS 3 between 6 and 14 GPa have distinct low-temperature magnetic structures comprising zAFM-I and zAFM-II, respectively (Fig. 1).…”

“…1). Moreover, long-range magnetic ordering is lost in the second high-pressure phase (HP-II) between 14 and 18 GPa [34]. The relative stability, vibrational signatures, and nature of these magnetically ordered structures need to be understood better.…”

Spatially resolved optical spectroscopy in extreme environment of low temperature, high magnetic fields and high pressure

“…The low-temperature Raman scattering response of FePS 3 includes a doubly degenerate antiferromagnetic magnon excitation close to 122 cm −1 identified by both its peculiar temperature dependence 21 , and recently, by its evolution with an applied magnetic field 9,22,23 . The properties of FePS 3 under pressure have been described recently from the viewpoints of X-ray diffraction 24 and of neutron scattering 25 . We present in Fig.…”

Comparative structural evolution under pressure of powder and single crystals of the layered antiferromagnet FePS$_3$

“…Previous high-pressure work [6][7][8][9] has demonstrated the occurrence of two structural transitions under pressure in powder samples of FePS 3 . The first, at a critical pressure of 4 GPa, is characterised as a shear of the weakly-coupled ab planes along the crystallographic a direction, maintaining the ambient pressure C2/m space group whilst reducing the angle β to very nearly 90° [6].…”

“…One model attributes this volume reduction to a collapse of the inter-planar spacing with a simultaneous symmetry increase to a trigonal P 31m space group [6]; the other to a shrinking of the Fe 2+ honeycombs, an effect within the ab planes, maintaining a monoclinic structure [10]. This impact of this higher-pressure structural transition on the magnetism in the system is also the subject of contradictory findings, with indirect results from x-ray emission spectroscopy measurements [10] contradicted by neutron diffraction [9].…”