Elastic anomaly for SrTiO_3 thin films grown on Si(001)

摘要

X-ray diffraction measurements have revealed a negative Poisson's ratio for SrTiO_3 thin films grown on Si(001). X-ray absorption tine-structure measurements demonstrate that this elastic anomaly is driven by the interfacial polarization of the SrTiO_3 layers. First-principles density-functional calculations support these conclusions. It is suggested that this phenomenon may be common for heteroepitaxial growth of materials that possess an ionic polarizability.