High-pressure phase transformation and metastable phases of a Si0.29Ge0.71 alloy using a diamond anvil cell
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2025-08-18 |
| Journal | Applied Physics Letters |
| Authors | Yoshifumi Ikoma, Yuma Sato, Hirokazu Kadobayashi, Saori I. Kawaguchi, Seung Zeon Han |
| Institutions | Korea Institute of Materials Science, Japan Aerospace Exploration Agency |
Abstract
Section titled āAbstractāWe investigated the high-pressure phase transformation of a Si0.29Ge0.71 alloy grown by a traveling liquidus-zone (TLZ) method. The TLZ-grown Si0.29Ge0.71 alloy was subjected to high pressures of up to ā¼15 GPa using a diamond anvil cell. In situ synchrotron X-ray diffraction (XRD) and micro-Raman measurements revealed the appearance of a tetragonal Ī²-Sn phase at 12.1 GPa. A weakened residual diamond-cubic (dc) diffraction peak together with dominant Ī²-Sn peaks was present at 15.2 GPa. Upon depressurization, a metastable rhombohedral r8 phase appeared at 8.4 GPa. When depressurized to ambient pressure, the XRD profile showed an almost body-centered-cubic bc8 phase with residual weak r8 and dc diffraction peaks. No appreciable Raman peaks were observed upon depressurization down to 4.1 GPa, but weak peaks appeared at ā¼283 and ā¼396 cmā1 at ambient pressure. Theoretical calculations based on density functional perturbation theory indicated that the observed peaks were not related to bc8 but rather to hexagonal diamond (hd). These results indicate that a bc8 ā hd phase transformation was induced by laser heating during the Raman measurement.