Depressed charge gap in the triangular-lattice Mott insulator κ−(ET)2Cu2(CN)3
- We have investigated polarized optical conductivity for the triangular-lattice Mott insulator κ−(ET)2Cu2(CN)3 over the photon-energy range of E=8meV–5eV. This compound is located far from the metal-insulator phase boundary in the bandwidth-controlled phase diagram of κ−(ET)2X salts and consequently strong charge correlations are expected. However, its ground-state optical conductivity spectrum for polarizations within the bc plane shows no distinct charge gap in the energy range investigated, i.e., it is considerably smaller than Δ≈110meV, which was previously reported for the barely insulating κ−(ET)2Cu[N(CN)2]Cl [Kornelsen et al., Solid State Commun. 81, 343 (1992)]. We attribute the pseudo-gap-like nature of the optical spectra to strong spin fluctuations emerging in an isotropic triangular lattice. The midinfrared peak is analyzed in terms of Coulomb interaction and κ−(ET)2Cu2(CN)3 is characterized by intermediate strength of electron correlation.
Author: | István KézsmárkiORCiDGND, Y. Shimizu, G. Mihály, Y. Tokura, K. Kanoda, G. Saito |
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URN: | urn:nbn:de:bvb:384-opus4-442086 |
Frontdoor URL | https://opus.bibliothek.uni-augsburg.de/opus4/44208 |
ISSN: | 1098-0121OPAC |
ISSN: | 1550-235XOPAC |
Parent Title (English): | Physical Review B |
Publisher: | American Physical Society (APS) |
Type: | Article |
Language: | English |
Year of first Publication: | 2006 |
Publishing Institution: | Universität Augsburg |
Release Date: | 2018/11/29 |
Volume: | 74 |
Issue: | 20 |
First Page: | 201101(R) |
DOI: | https://doi.org/10.1103/physrevb.74.201101 |
Institutes: | Mathematisch-Naturwissenschaftlich-Technische Fakultät |
Mathematisch-Naturwissenschaftlich-Technische Fakultät / Institut für Physik | |
Mathematisch-Naturwissenschaftlich-Technische Fakultät / Institut für Physik / Lehrstuhl für Experimentalphysik V | |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
Licence (German): | Deutsches Urheberrecht |