EVIDENCE FOR PYROELECTRICITY IN SINGLE VARIANT SPONTANEOUSLY ORDERED GAINP2

The random alloy GaInP2 exhibits the 43mBAR point group symmetry and thus does not posses a unique polar direction. In contrast, spontaneously ordered GaInP2 exhibits the 3m point group symmetry which can give rise to pyroelectricity along the 3-fold symmetry axis or ordering direction. Due to the similarity between the Ga and In cations, any temperature variation induced polarization is expected to be very small compared with typical pyroelectrics such as hexagonal CdS. Our study yields the first experimental evidence for pyroelectricity in single variant spontaneously ordered GaInP2. The experiments involve low frequency laser heating and pyroelectric current measurement using a lock-in detection technique.