Potential room-temperature multiferroicity in cupric oxide under high pressure

CuO, known to be multiferroic (MF) from ${T}_{L}\phantom{\rule{4pt}{0ex}}=\phantom{\rule{4pt}{0ex}}213\phantom{\rule{4pt}{0ex}}\mathrm{K}$ ${T}_{N}\phantom{\rule{4pt}{0ex}}=\phantom{\rule{4pt}{0ex}}230\phantom{\rule{4pt}{0ex}}\mathrm{K}$ at ambient pressure, has been the subject of debates about its ability exhibit multiferroicity room temperature (RT) under high hydrostatic pressure. Here we address this question based on theoretical and experimental investigations. The influence pressure ${T}_{L}$ ${T}_{N}$ estimated ab initio calculations combined with classical Monte-Carlo simulations a quasi-1D antiferromagnetic analytical model. From side, electric permittivity anomalies related ferroelectric transitions have followed dielectric measurements single crystals up 6.1 GPa. We show that below which MF state forms increases linearly higher hitherto supposed, indeed our calculations, should exceed RT above 20