Anomalous electron emission from lithium niobate and lithium tantalate single crystals

Anomalous electron emission from the (10 (1) over bar 4) surface of LiNbO3 and LiTaO3 single crystals excited by soft x radiation has been discovered and is investigated, The absence of anomalous emission from the (10 (1) over bar 0) face of these single crystals is established. The experimental results confirm the theoretical conclusions that the anomalous emission is caused by the presence of a maximum in the distribution of the potential in the near-surface layer, The dependence of Be lifetime tau of the anomalous emission on the dielectric constant epsilon of the ferroelectric is calculated. (C) 1997 American Institute of Physics.