The Electronic Structure and Secondary Pyroelectric Properties of Lithium Tetraborate

We review the pyroelectric properties and electronic structure of Li(2)B(4)O(7)(110) and Li(2)B(4)O(7)(100) surfaces. There is evidence for a pyroelectric current along the [110] direction of stoichiometric Li(2)B(4)O(7) so that the pyroelectric coefficient is nonzero but roughly 10(3) smaller than along the [001] direction of spontaneous polarization. Abrupt decreases in the pyroelectric coefficient along the [110] direction can be correlated with anomalies in the elastic stiffness [Formula: see text] contributing to the concept that the pyroelectric coefficient is not simply a vector but has qualities of a tensor, as expected. The time dependent surface photovoltaic charging suggests that surface charging is dependent on crystal orientation and doping, as well as temperature.