Vapour growth and piezoelectric effect of indium thiophosphate, InPS4

Polyhedral crystals of InPS4 with edge lengths up to 10 mm have been grown by iodine transport, employing a novel technique in a vertical temperature gradient. An apparatus for measuring the piezoelectric moduli of relatively small crystals by a dynamic, non-resonant method has been developed. The four piezoelectric moduli of InPS4 have been determined. They differ considerably in magnitude, one of them (d36) being about 10 times as large as the maximal modulus (d11) of quartz.