| 1. |
- Nag, Abhishek, et al.
(author)
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Origin of the Spin-Orbital Liquid State in a Nearly J=0 Iridate Ba3ZnIr2O9
- 2016
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In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 116:9
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Journal article (peer-reviewed)abstract
- We show using detailed magnetic and thermodynamic studies and theoretical calculations that the ground state of Ba3ZnIr2O9 is a realization of a novel spin-orbital liquid state. Our results reveal that Ba3ZnIr2O9 with Ir5+ (5d(4)) ions and strong spin-orbit coupling (SOC) arrives very close to the elusive J = 0 state but each Ir ion still possesses a weak moment. Ab initio density functional calculations indicate that this moment is developed due to superexchange, mediated by a strong intradimer hopping mechanism. While the Ir spins within the structural Ir2O9 dimer are expected to form a spin-orbit singlet state (SOS) with no resultant moment, substantial frustration arising from interdimer exchange interactions induce quantum fluctuations in these possible SOS states favoring a spin-orbital liquid phase down to at least 100 mK.
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| 2. |
- Wojek, Bastian M., et al.
(author)
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The J(eff)=1/2 insulator Sr3Ir2O7 studied by means of angle-resolved photoemission spectroscopy
- 2012
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In: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 24:41, s. 415602-
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Journal article (peer-reviewed)abstract
- The low-energy electronic structure of the J(eff) = 1/2 spin-orbit insulator Sr3Ir2O7 has been studied by means of angle-resolved photoemission spectroscopy. A comparison of the results for bilayer Sr3Ir2O7 with available literature data for the related single-layer compound Sr2IrO4 reveals qualitative similarities and similar J(eff) = 1/2 bandwidths for the two materials, but also pronounced differences in the distribution of the spectral weight. In particular, photoemission from the J(eff) = 1/2 states appears to be suppressed. Yet, it is found that the Sr3Ir2O7 data are in overall better agreement with band-structure calculations than the data for Sr2IrO4.
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| 3. |
- Amin, S., et al.
(author)
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Behavioral Modeling and Linearization of Crosstalk and Memory Effects in RF MIMO Transmitters
- 2014
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In: IEEE Transactions on Microwave Theory and Techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 62:4, s. 810-823
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Journal article (peer-reviewed)abstract
- This paper proposes three novel models for behavioral modeling and digital pre-distortion (DPD) of nonlinear 2 x 2 multiple-input multiple-output (MIMO) transmitters in the presence of crosstalk. The proposed models are extensions of the single-input single-output generalized memory polynomial model. Three types of crosstalk effects were studied and characterized as linear, nonlinear, and nonlinear & linear crosstalk. A comparative study was performed with previously published models for the linearization of crosstalk in a nonlinear 2 x 2 MIMO transmitter. The experiments indicate that, depending on the type of crosstalk, the selection of the correct model in the transmitter is necessary for behavioral modeling and sufficient DPD performance. The effects of coherent and partially noncoherent signal generation on the performance of DPD were also studied. For crosstalk levels of 30 dB, the difference in the normalized mean square error and adjacent channel power ratio was found to be 3-4 dB between coherent and partially noncoherent signal generation.
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| 4. |
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| 5. |
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| 6. |
- Niklasson, GA, et al.
(author)
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Surface roughness of pyrolytic tin dioxide films evaluated by different methods
- 2000
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In: THIN SOLID FILMS. - : ELSEVIER SCIENCE SA. - 0040-6090. ; 359:2, s. 203-209
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Journal article (peer-reviewed)abstract
- The scaling of surface roughness in thin spray pyrolyzed fluorinated tin dioxide films of different thicknesses was obtained from atomic force microscopy. The data show that, within experimental uncertainties, the effective dimensionality of the surface i
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