Pressure-Induced Structural Phase Transition and a Special Amorphization Phase of Two-Dimensional Ferromagnetic Semiconductor Cr2Ge2Te6

Abstract

Layered transition-metal trichalcogenides have become one of the research frontiers as two-dimensional magnets and candidate materials used for phase-change memory devices. Herein we report the high-pressure synchrotron X-ray diffraction and resistivity measurements on Cr2Ge2Te6 (CGT) single crystal by using diamond anvil cell techniques, which reveal a mixture of crystalline-to-crystalline and crystalline-to-amorphous transitions taking place concurrently at 18.3-29.2 GPa. The polymorphic transition could be interpreted by atomic layer reconstruction and the amorphization could be understood in connection with randomly flipping atoms into van der Waals gaps. The amorphous (AM) phase is quenchable to ambient conditions. The electrical resistance of CGT shows a bouncing point at ~ 18 GPa, consistent with the polymorphism phase transition. Interestingly, the high-pressure AM phase exhibits metallic resistance with the magnitude comparable to that of high-pressure crystalline phases, whereas the resistance of the AM phase at ambient pressure fails to exceed that of the crystalline phase, indicating that the AM phase of CGT appeared under high pressure is quite unique and similar behavior has never been observed in other phase-change materials. The results definitely would have significant implications for the design of new functional materials.

14 pages,7 figures, 2 tables, 1 supporting information. JPCC in press

References in corpus (6)

• Electric Field Effect in Atomically Thin Carbon Films
• Discovery of intrinsic ferromagnetism in 2D van der Waals crystals
• Gate-tunable Room-temperature Ferromagnetism in Two-dimensional Fe${}_3$GeTe${}_2$
• Tricritical behavior of two-dimensional intrinsic ferromagnetic semiconducting CrGeTe3
• Critical behavior of quasi-two-dimensional semiconducting ferromagnet CrGeTe${}_3$
• Slip line growth as a critical phenomenon

Cited by in corpus (10)

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• Nearly room temperature ferromagnetism in pressure-induced correlated metallic state of van der Waals insulator CrGeTe${}_3$
• Pressure control of the magnetic anisotropy of the quasi-two-dimensional van der Waals ferromagnet Cr${}_2$Ge${}_2$Te${}_6$
• Lattice dynamics and phonon dispersion of van der Waals layered ferromagnet Fe3GaTe2
• Short-range Crystalline Order-Tuned Conductivity in Cr${}_2$Si${}_2$Te${}_6$ van der Waals Magnetic Crystals
• Polaronic Conductivity in Cr${}_2$Ge${}_2$Te${}_6$ Single Crystals
• Pressure evolution of electronic structure and magnetism in the layered van der Waals ferromagnet CrGeTe${}_3$
• Pressure tuning of intrinsic and extrinsic sources to the anomalous Hall effect in CrGeTe${}_3$
• Spontaneously formed phonon frequency combs in van der Waals solid CrXTe${}_3$ (X=Ge,Si)
• Near room-temperature ferromagnetism from double-exchange in the van der Waals material CrGeTe${}_3$: evidence from optical conductivity under pressure