Abstract
Density functional theory is used to estimate the e11 and d11 piezoelectric elements in the trigonal form of BiPO4. The calculated values, e11 = -1.46 C/m2 and d11 = -22.84 pC/N at 0 K, are significantly higher than those predicted in a-quartz-type materials but require experimental confirmation. The polar E-modes below 100 cm-1 are at the origin of the piezoelectric efficiency.