Negative thermal expansion property of β-Cu2V2O7

Wang, Hui; Yang, Ming‐Lin; Chao, Mingju; Guo, Juan; Gao, Qilong; Jiao, Yajie; Tang, Xinbo; Liang, Erjun

doi:10.1016/j.ssi.2019.115086

Cited by 32 publications

(27 citation statements)

References 43 publications

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“…This is important because it suggests that the relative rotation of the VO 4 units (which comprise the V 2 O 7 dimers) is an important characteristic of the volume collapse. This supports previous ambient pressure investigations which suggest that mutual rotation of the VO 4 molecular units, suggested by vibrational spectroscopy measurements, underpin the negative thermal expansion mechanism. , …”

Section: Resultssupporting

confidence: 90%

“…The primary mechanism for the NTE is believed to relate primarily to a transverse vibrational mode associated with the oxygen atom which bridges the VO 4 tetrahedra in the V 2 O 7 units (O 3 V–O–VO 3 ). The V 2 O 7 units interlink the chains of edge-sharing CuO x units; therefore, a vibrational mode perpendicular to the V–O–V bridge causes a reduction in the time-averaged distance between the vanadium atoms, thereby pulling the layers closer together and reducing the unit volume. , …”

Section: Resultsmentioning

confidence: 99%

“…The V 2 O 7 units interlink the chains of edge-sharing CuO x units; therefore, a vibrational mode perpendicular to the V−O−V bridge causes a reduction in the time-averaged distance between the vanadium atoms, thereby pulling the layers closer together and reducing the unit volume. 14,15 Since the layers lie the ab-plane, a reduction in the lattice constant c corresponds to a decrease in the interlayer distance. As shown in Figure 5c, all lattice constants for both phases decrease monotonically with increasing pressure.…”

Section: Resultsmentioning

confidence: 99%

“…β-Cu 2 V 2 O 7 has a number of interesting and useful properties; for example, β-Cu 2 V 2 O 7 is a semiconducting antiferromagnetic material which has an (indirect) electronic band gap energy of ∼2 eV, which is optimal for absorbing energy within the solar range . β-Cu 2 V 2 O 7 also exhibits interesting magnetic properties, due to its spin-1/2 honeycomb lattice of Cu 2+ [3d 9 ] ions, including quasi-1D antiferromagnetism. − Finally, β-Cu 2 V 2 O 7 is also known to exhibit a negative thermal expansion at ambient pressure. , None of the Cu 2 V 2 O 7 phases has previously been studied at high pressure; therefore, an additional motivation for this high-pressure investigation is to study mechanical similarities between the negative thermal expansion and pressure-induced volume decrease.…”

Section: Introductionmentioning

confidence: 99%

“…11−13 Finally, β-Cu 2 V 2 O 7 is also known to exhibit a negative thermal expansion at ambient pressure. 14,15 None of the Cu 2 V 2 O 7 phases has previously been studied at high pressure; therefore, an additional motivation for this high-pressure investigation is to study mechanical similarities between the negative thermal expansion and pressure-induced volume decrease.…”

mentioning

confidence: 99%

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Pressure-Induced Phase Transition and Band Gap Decrease in Semiconducting β-Cu₂V₂O₇

et al. 2022

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The understanding of the interplay between crystal structure and electronic structure in semiconductor materials is of great importance due to their potential technological applications. Pressure is an ideal external control parameter to tune the crystal structures of semiconductor materials in order to investigate their emergent piezo-electrical and optical properties. Accordingly, we investigate here the high-pressure behavior of the semiconducting antiferromagnetic material β-Cu 2 V 2 O 7 , finding it undergoes a pressure-induced phase transition to γ-Cu 2 V 2 O 7 below 4000 atm. The pressure-induced structural and electronic evolutions are investigated by single-crystal X-ray diffraction, absorption spectroscopy and ab initio density functional theory calculations. β-Cu 2 V 2 O 7 has previously been suggested as a promising photocatalyst for water splitting. Now, these new results suggest that β-Cu 2 V 2 O 7 could also be of interest with regards to barocaloric effects, due to the low phase -transition pressure, in particular because it is a multiferroic material. Moreover, the phase transition involves an electronic band gap decrease of approximately 0.2 eV (from 1.93 to 1.75 eV) and a large structural volume collapse of approximately 7%.

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%