Phase Transitions in GeTe at Hydrostatic Pressure up to 9.3 GPa

Khvostantsev, L. G.; Sidorov, V. A.; Shelimova, L. E.; Abrikosov, N. Kh.

doi:10.1002/pssa.2210740122

Cited by 15 publications

(5 citation statements)

References 23 publications

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“…It can be seen that the resistance decreases rapidly with increasing pressure. Intriguingly, a noticeable bump is observed in the resistance-pressure curve at about 4 GPa, which is consistent with the result reported by Khvostantsev et al [42] and this phenomenon should be correlated with a structural phase transition from R3m to Fm3m. Upon further compression, the resistance-pressure curve becomes flat- tened at pressures above 11 GPa, which could be interpreted as a semiconductor-metal transition in GeTe, the result is in agreement with previous theoretical work that the band gap of Fm3m phase is closed at high pressure [32].…”

Section: Resultssupporting

confidence: 92%

Pressure-induced structural transitions between successional superconducting phases in GeTe

Wang¹,

Wang²,

Ma³

et al. 2021

J. Phys.: Condens. Matter

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Being a best-known prototype of phase-change materials, GeTe was reported to possess many high-pressure phases, whose structural evolution and superconductivity remain under debate for decades. Herein, we systematically investigated the pressure dependence of electrical transport and the structural evolution of the GeTe via in situ angle-dispersive synchrotron x-ray diffraction and resistance measurements up to 55 GPa. At room temperature, the structural phase transitions from the initial rhombohedral phase to the phase, and then to an orthorhombic Pnma phase, were observed at pressures of about 4 and 13.4 GPa, respectively. Furthermore, the metallization occurred at around 11 GPa, where the superconductivity could also be observed. With increasing pressure, the superconducting transition temperature increases monotonically from 5.7 to 6.4 K and then is independent of pressure above 23 GPa in the pure Pnma phase. These results provide insights into the pressure-dependent evolution of the structure and superconductivity in GeTe and have implications for the understanding of other IV–VI semiconductors at high pressure.

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Section: Resultssupporting

confidence: 92%

Pressure-induced structural transitions between successional superconducting phases in GeTe

Wang¹,

Wang²,

Ma³

et al. 2021

J. Phys.: Condens. Matter

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“…This is particularly evident in layer structures. Therefore, the controversies on the previous studies may be due to non-hydrostaticity of the applied pressure because the group IV-VI compounds are made up of puckered layers sensitive to shear stress [17,18]. On the other hand, the electrical resistance measurement on GeSe [19] showed monotonically decreases with increasing pressure, which was interpreted in terms of a metallization above 25GPa.…”

Section: Introductionmentioning

confidence: 99%

Structural transitions and metallization in dense GeS

2016

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We have studied the pressure-induced structural and electronic transitions of GeS to 49 GPa, using diamond anvil cells, micro-confocal Raman spectroscopy, synchrotron angle-resolved x-ray diffraction and electrical resistance measurements. The results indicate that layered GeS phase I (Pnma) undergoes two structural phase transitions: first to phase II (P2 1 /m) at ~9 GPa and then phase III (Cmcm) at ~32 GPa. These transitions occur sluggishly over large pressure ranges and accompany an increase of the nearest coordination number of Ge and S atoms from three in phase I and II to five in phase III, resulting in an extended network of densely packed layer structures in phase III. We suggest anisotropic-compression enhanced shears to be responsible for the transitions.The phase II also undergoes an electronic insulator-metal transition and becomes metallic above 20 GPa, The temperatures dependent resistance change of phase II further indicates a gradual band-gap closing of phase II (P2 1 /m).

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“…At room temperature, one noticeable jump was observed by Wang et al in the resistance–pressure curve at approximately 4 GPa, which was assigned to the R 3 m -B1 transition . However, no conspicuous changes in resistivity were observed between 3 and 6 GPa in refs , , and with a remarkable increase caused by the formation of the orthorhombic phase observed at ∼15 under nonhydrostatic pressure (9 GPa under hydrostatic conditions). On the other hand, although GeTe is a typical semiconductor at ambient pressure, it often presents a metal-like resistivity and superconductivity ( T c ≤ 1.5 K) with decreasing temperature, which can be attributed to Ge deficiency. − Under compression, however, several divergent results have been reported.…”

Section: Introductionmentioning

confidence: 91%

Pressure-Induced Alloying and Superconductivity in GeTe

Cheng,

Yao,

et al. 2024

Chem. Mater.

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Here, we systematically investigated the pressure dependence of electronic transport and the crystal structure of GeTe using multiple methods under various hydrostatic conditions. The experiments indicated that a progressive structural evolution occurred from the ambient rhombohedral phase (space group [SG]: R3m) to the rock-salt phase (SG: Fm3̅ m) and then to an orthorhombic phase (SG: Pnma). Above 50 GPa, we determined that GeTe developed into a body-centered cubic (bcc, SG: Im3̅ m) structure, which consisted of a site-disordered alloy. An unambiguous correlation between superconductivity and phase transitions was observed in this compound, and the maximum superconducting transition temperature (T c ) was approximately 7.5 ± 0.2 K at 30.0(1) GPa. Finally, the key effect of ionic size and charge transfer between the Ge and Te ions on the formation of site-disordered alloys in GeTe was discussed.

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Phase Transitions in GeTe at Hydrostatic Pressure up to 9.3 GPa

Cited by 15 publications

References 23 publications

Pressure-induced structural transitions between successional superconducting phases in GeTe

Pressure-induced structural transitions between successional superconducting phases in GeTe

Structural transitions and metallization in dense GeS

Pressure-Induced Alloying and Superconductivity in GeTe

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