Raman signatures of quadratic band touching state and strong spin-phonon coupling in pyrochlore iridates Formula Presented

Rosalin, M and Telang, P and Singh, S and Muthu, DVS and Sood, AK (2023) Raman signatures of quadratic band touching state and strong spin-phonon coupling in pyrochlore iridates Formula Presented. In: Physical Review B, 108 (3).

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Abstract

In this work, we report low-temperature Raman spectroscopic measurement to investigate the temperature dependence of phonons and magnetic as well as electronic excitations in Formula Presented for Formula Presented, 0.02, 0.035, 0.05, and 0.10. A strong spin-phonon coupling induced phonon renormalization is observed below magnetic transition temperature Formula Presented for samples with Formula Presented. An underlying broad continuum attributed to pronounced spin-spin correlations is observed below Formula Presented for pure Formula Presented. Significant phonon anomalies at lower temperatures, much below Formula Presented, for Formula Presented and 0.02, are observed and are attributed to a possible crossover into the Weyl semimetal state. Most interestingly, we observe clear signatures of quadratic band touching in Formula Presented and 0.10 systems in terms of a broad electronic continuum at low temperatures analyzed using the Raman susceptibility for a non-Fermi liquid, corroborating the inference from recent transport measurements.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Additional Information:	The copyright for this article belongs to the American Physical Society.
Keywords:	Fermi liquids; Fermions; Temperature distribution, Electronic excitation; Lows-temperatures; Magnetic excitations; Pyrochlores; Raman signatures; Raman spectroscopic; Renormalization; Spectroscopic measurements; Spin-phonon coupling; Temperature dependence, Phonons
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	29 Nov 2023 09:36
Last Modified:	29 Nov 2023 09:36
URI:	https://eprints.iisc.ac.in/id/eprint/82909

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