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

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 beta-Cu2V2O7, finding it undergoes a pressure-induced phase transition to gamma-Cu2V2O7 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. beta-Cu2V2O7 has previously been suggested as a promising photocatalyst for water splitting. Now, these new results suggest that beta-Cu2V2O7 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%.

Automated summary

The interplay between crystal structure and electronic structure in semiconductor materials is crucial for their potential technological applications. In this study, the high-pressure behavior of semiconducting antiferromagnetic material beta-Cu2V2O7 was investigated, revealing a pressure-induced phase transition to gamma-Cu2V2O7 below 4000 atm. The structural and electronic changes were studied using techniques such as single-crystal X-ray diffraction, absorption spectroscopy, and ab initio density functional theory calculations. These findings not only shed light on the potential barocaloric effects of beta-Cu2V2O7, but also suggest its significance as a multiferroic material with a decreased electronic band gap and a significant structural volume collapse.