Near-band gap electronic structure of the tetragonal rare-earth cuprates<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>R</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mtext>CuO</mml:mtext></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>and the bismuth cuprate<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Bi</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msu

Pisarev, R. V.; Павлов, В. В.; Kalashnikova, A.M.; Moskvin, A. S.

doi:10.1103/physrevb.82.224502

Cited by 27 publications

(14 citation statements)

References 39 publications

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“…Specifically, on-site Coulomb repulsion U is essential to describe the charge transfer process while it plays almost no role for local excitations. Finally, our findings demonstrate that the electrodynamic response of Herbertsmithite and its analogues is similar in nature to the parent compounds of high-T c cuprates, being chargetransfer rather than Mott insulators [4,6,34,46]. The project was supported by the Deutsche Forschungsgemeinschaft (DFG) through grants SFB/TR 49.…”

Section: Cumentioning

confidence: 64%

Nature of optical excitations in the frustrated kagome compound herbertsmithite

et al. 2017

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Optical conductivity measurements are combined with density functional theory calculations in order to understand the electrodynamic response of the frustrated Mott insulators Herbertsmithite ZnCu3(OH)6Cl2 and the closely-related kagome-lattice compound Y3Cu9(OH)19Cl8. We identify these materials as charge-transfer rather than Mott-Hubbard insulators, similar to the high-Tc cuprate parent compounds. The band edge is at 3.3 and 3.6 eV, respectively, establishing the insulating nature of these compounds. Inside the gap, we observe dipole-forbidden local electronic transitions between the Cu 3d orbitals in the range 1-2 eV. With the help of ab initio calculations we demonstrate that the electrodynamic response in these systems is directly related to the role of on-site Coulomb repulsion: while charge-transfer processes have their origin on transitions between the ligand band and the Cu 3d upper Hubbard band, local d-d excitations remain rather unaffected by correlations.Since the discovery of high-T c cuprates, the physics of strongly correlated materials has been at the forefront of research in condensed matter physics. The relationship between correlations, unconventional superconductivity, quantum-spin-liquid behavior and other exotic states of matter has been intensely debated. While at the level of model theories one can introduce criteria to quantify the degree of correlation, such as the ratio U/W , where U is the on-site Coulomb repulsion and W is the singleparticle bandwidth, the quantification in many materials is not that straightforward. The effect of correlations usually shows up as mass renormalization, band narrowing, or as opening or enhancement of the band gap [1, 2]. Cu+2 ions are, arguably, the most strongly correlated among d transition metals [3][4][5][6]. They are key ingredients of high-T c cuprates and have been widely investigated in the last decades. A recent revival of interest in Cu-based materials was triggered by the discovery of geometrically frustrated cuprates that seem to exhibit spin-liquid properties [7][8][9][10][11][12][13][14][15][16] and may even harbor unconventional superconductivity with higher angular momenta than existing superconductors [17] or further topological phases [18] although synthesis seems to be difficult [19].In this work we investigate the origin of the optical excitations in the spin-liquid candidate Herbertsmithite and concentrate on the following conceptual issue: which measurable properties in correlated systems are strongly affected by correlation effects and which are not? We will show, experimentally and theoretically, that in a single experimental probe, namely optical conductivity, one can simultaneously observe properties dramatically influenced by Coulomb (Mott-Hubbard) correlation effects, and those that are hardly affected at all.One can distinguish two types of optical absorption processes, depicted in Fig. 1. On the one hand, we have the "charge-transfer process", that in its simple form can be described as creating a hole and an electron res...

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Section: Cumentioning

confidence: 64%

Nature of optical excitations in the frustrated kagome compound herbertsmithite

et al. 2017

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“…respectively [27]. From the view of thermodynamic process, electrons transfer will occur from conduction band of n-type ZnO to that of p-type CuO, while holes immigrate will transfer in valence band from p-type CuO to n-type ZnO at the interfaces of the ZnO-CuO IO samples [28]. This process will result in new Fermi Fig.…”

Section: Xpsmentioning

confidence: 96%

Three-dimensional ordered ZnO–CuO inverse opals toward low concentration acetone detection for exhaled breath sensing

Xie

Xing

et al. 2015

Sensors and Actuators B: Chemical

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“…The band gap of CuO is 1.35 eV, and its electron affinity is 4.07 eV. From a thermodynamic, the electrons will transfer from CB of ZnO to CuO, while the holes will oppositely immigrate from VB of CuO to ZnO . The modified CuO nanostructures can act as a strong acceptor of electrons from ZnO .…”

Section: Resultsmentioning

confidence: 99%

Fabrication of a Disordered Mesoporous ZnO Matrix Modified by CuO Film as High‐Performance NO_x Sensor

Liu

et al. 2018

ChemistrySelect

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Herein, the ZnO matrix with disordered mesoporous (disordered mesoporous ZnO, DM‐ZnO) was prepared by sol‐gel template method. For the first time, a layer Cu thin film was coated on the surface of the DM‐ZnO matrix to increase the conductivity of matrix by chemical deposition method (CDM), an electro‐deposition method (EDM) was creatively used to thicken the Cu thin film, a layer CuO thin film was coated on the surface of the DM‐ZnO matrix by the high temperature calcination method, and an n‐p heterojunction disordered mesoporous CuO/ZnO composite (CZC) was fabricated. The morphology, structure and gas sensing performance toward NOx of the CZC sample were characterized. The CZC sample showed the flower‐like structures which were composed of petaloid particles, and the particles length was about 450 nm, the width was about 150 nm, and the disordered mesoporous distributed on the surface of the particles, the pore size was about 2.1 nm. Many sensors at high temperatures have been reported in the literature, however, sensors at high temperature had much drawbacks. The CZC sample showed the much higher gas response property to NOx at room temperature, whose response to 100 ppm NOx gas reached to 11.73, the response time was only 11.5 s, and the detection limit was only 0.5 ppm. And the prepared material had an expansive application prospect in toxic gas detection field.

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Near-band gap electronic structure of the tetragonal rare-earth cupratesR2CuO4and the bismuth cuprateBi2

Cited by 27 publications

References 39 publications

Nature of optical excitations in the frustrated kagome compound herbertsmithite

Nature of optical excitations in the frustrated kagome compound herbertsmithite

Three-dimensional ordered ZnO–CuO inverse opals toward low concentration acetone detection for exhaled breath sensing

Fabrication of a Disordered Mesoporous ZnO Matrix Modified by CuO Film as High‐Performance NO_x Sensor

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Near-band gap electronic structure of the tetragonal rare-earth cupratesR2CuO4and the bismuth cuprateBi2

Cited by 27 publications

References 39 publications

Nature of optical excitations in the frustrated kagome compound herbertsmithite

Nature of optical excitations in the frustrated kagome compound herbertsmithite

Three-dimensional ordered ZnO–CuO inverse opals toward low concentration acetone detection for exhaled breath sensing

Fabrication of a Disordered Mesoporous ZnO Matrix Modified by CuO Film as High‐Performance NOx Sensor

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Fabrication of a Disordered Mesoporous ZnO Matrix Modified by CuO Film as High‐Performance NO_x Sensor