Thermal stimulated current response in cupric oxide single crystal thin   films over a wide temperature range
  Cupric oxide single crystal thin films were grown by plasma-assisted molecular beam epitaxy. X-ray diffraction, Raman spectrum and in situ reflection high-energy electron diffraction show that the thin films are 2x2 reconstructed with an in-plane compression and out-of-plane stretching. Thermal stimulated current measurement indicates that the electric polarization response presents in the special 2D cupric oxide single crystal thin film over a wide temperature range from 130 K to near-room temperature. We infer that the abnormal electric response involves the changing of phase transition temperature induced by structure distortion, the spin frustration and magnetic fluctuation effect of short-range magnetic order, or the combined action of both two factors mentioned above. This work suggests a promising clue for finding new room temperature single phase multiferroics or tuning phase transition temperature. 
K. G. Yang, S. X. Wu, F. M. Yu, W. Q. Zhou, Y. J. Wang, M. Meng, G. L.   Wang, Y. L. Zhang and S. W. Li
cond-mat.mtrl-sci