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dc.date.accessioned | 2021-09-28T13:57:22Z | |
dc.date.available | 2021-09-28T13:57:22Z | |
dc.date.issued | 2020-10-12 | |
dc.identifier.uri | http://sedici.unlp.edu.ar/handle/10915/125735 | |
dc.description.abstract | We report the temperature dependent THz to mid-infrared response of hexagonal-ErMnO3 using absorption, reflectivity, and emissivity techniques from 2 K to 1700 K. At low temperatures, lowest frequency vibrational modes which extend up the lock-in ferroelectric temperature, coexist with paramagnon excitations and are associated with well-defined crystal field Rare Earth pure magnetic replicas in an intriguing phonon-magnetic convergence enhancing the multiferroic character of h-ErMnO3. Increasing the temperature, a number of vibrational bands close to the space group predicted undergo profile broadening and softening. In particular, a distinctive set of bands in the 288-329 cm-1 (300 K) range has a component whose profile is carrier screened becoming nearly fully blurred in the intermediate phase between ~830 K and ~1500 K. Below TC ~830 K this asymmetric band, having one component still partially screened, further splits as spin phonon interaction and the tripling of the unit cell takes place revealing at TN ~79 K a delicate balance of long- and short-range interactions. Ambient Raman scattering brings up evidence of a Fröhlich resonance due to Coulomb interactions between carriers and the macroscopic field linked to the corresponding longitudinal optical phonon mode. We found it is dynamically correlated to the hexagonal c-axis negative thermal expansion. Quantitative analyses of the mid-infrared (MIR) optical conductivity show that also plays a role in small polarons and mediates in high temperature bipolarones. Bipolaron profiles at high temperatures change as the sample opacity increases when at ~900 K straight stripes turn curly toward complex vortex-antivortex domain patterns in the paraelectric phase. At still higher temperatures a low frequency Drude contribution is triggered by electron hopping signaling an insulator-metal phase transition at ~1600 K while the MIR response suggests coexistence between single small polarons and bipolarons. On closing, we draw a parallel with improper ferroelectrics sustaining a lattice incommensurate intermediate phase and unit cell tripling. We argue that in the h-ErMnO3 (R=Rare Earth, Y) family of compounds the intermediate phase be considered incommensurate with onset at TINC ~1500 K and ferroelectric lock-in at TC ~830 K delimiting this regime in h-ErMnO3. | en |
dc.language | en | es |
dc.subject | Fröhlich resonance | es |
dc.subject | polarons | es |
dc.subject | bipolarons | es |
dc.subject | Phonon interactions | es |
dc.title | h-ErMnO3 absorbance, reflectivity and, emissivity in the THz to mid-infrared from 2 K to 1700 K | en |
dc.type | Articulo | es |
sedici.identifier.other | arXiv:2010.06341 | es |
sedici.identifier.other | doi:10.1103/physrevb.102.134305 | es |
sedici.identifier.issn | 2469-9950 | es |
sedici.identifier.issn | 2469-9969 | es |
sedici.title.subtitle | Carrier screening, Fröhlich resonance, small polarons, and bipolarons | en |
sedici.creator.person | Massa, Néstor Emilio | es |
sedici.creator.person | del Campo, Leire | es |
sedici.creator.person | Holldack, Karsten | es |
sedici.creator.person | Canizares, Aurélien | es |
sedici.creator.person | Phuoc, Vinh Ta | es |
sedici.creator.person | Kayser, Paula | es |
sedici.creator.person | Alonso, José Antonio | es |
sedici.subject.materias | Física | es |
sedici.subject.materias | Ciencias Exactas | es |
sedici.description.fulltext | true | es |
mods.originInfo.place | Centro de Química Inorgánica | es |
sedici.subtype | Preprint | es |
sedici.rights.license | Creative Commons Attribution 4.0 International (CC BY 4.0) | |
sedici.rights.uri | http://creativecommons.org/licenses/by/4.0/ | |
sedici.description.peerReview | peer-review | es |
sedici.relation.journalTitle | Physical Review B | es |
sedici.relation.journalVolumeAndIssue | vol. 102, no. 13 | es |