Thomas, A and Telang, P and Mishra, K and Cesnek, M and Bednarcik, J and Muthu, DVS and Singh, S and Sood, AK (2022) Role of spin-phonon and electron-phonon interactions in the phonon renormalization of (Eu1-xBix)2Ir2 O7 across the metal-insulator phase transition: Temperature-dependent Raman and x-ray studies. In: Physical Review B, 105 (7).
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Abstract
We report temperature-dependent Raman scattering and x-ray diffraction studies of pyrochlore iridates (Eu1-xBix)2Ir2O7, for x=0, 0.02, 0.035, 0.05, and 0.1. The temperature variation in Raman experiments spans from 4 to 300 K, covering the metal-insulator phase transition accompanied by paramagnetic-to-all-in/all-out (AIAO) spin ordering (TN). These systems also show a Weyl semimetal (WSM) phase at low temperatures (<�50K). The Ir-O-Ir bond bending mode A1g (510 cm-1) shows anomalous softening (for x=0.0, 0.02, 0.035, and 0.05) in the magnetically ordered AIAO state, arising primarily from the spin-phonon interaction due to the phonon modulation of the Dzyaloshinskii-Moriya spin-exchange interaction. The two stretching modes T2g1 (307 cm-1) and T2g2 (382 cm-1) harden significantly in the magnetic insulating phase. The T2g phonons (for x=0.0, 0.02, 0.035, and 0.05) also show anomalous temperature dependence of their mode frequencies above TN due to strong electron-phonon coupling. The signatures of the WSM state are observed clearly in phonon renormalization <50K (in x=0.02) due to strong electron-phonon interaction. Our experimental results establish strong magneto-elastic coupling below TN and significant electron-phonon interactions in the metallic phase above TN as well as in the low-temperature WSM state. © 2022 American Physical Society.
| Item Type: | Journal Article |
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| Publication: | Physical Review B |
| Publisher: | American Physical Society |
| Additional Information: | The Copyright for this article belongs to the Authors |
| Keywords: | Electron correlations; Electrons; Iridium compounds; Metal insulator boundaries; Metal insulator transition; Semiconductor insulator boundaries; Temperature distribution, Lows-temperatures; Metal-insulators phase transitions; Phase transition temperatures; Pyrochlores; Renormalization; Temperature dependent Raman scattering; Temperature variation; Temperature-dependent raman; X-ray diffraction studies; X-ray studies, Electron-phonon interactions |
| Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 12 May 2022 05:52 |
| Last Modified: | 12 May 2022 05:52 |
| URI: | https://eprints.iisc.ac.in/id/eprint/71628 |
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