First-principles study of thin-film properties of transition-metal oxide SrTcO_3

摘要

The structural and electronic properties of fully-relaxed thin-film SrTcO_3 are investigated using first-principles method. In contrast to the insulating property of the bulk SrTcO_3, the thin-film SrTcO_3 with a thickness of 8.06 A is found to be nearly metallic with a very small band gap of 0.17 eV. Its band structure meets the demands of being thermoelectric material. Moreover, thin-film SrTcO_3 is found to retain its bulk high magnetic ordering temperature (T_N) property, which suggests that it is applicable in high ambient temperatures. Comparison of the electronic/magnetic property of thin-film and bulk SrTcO_3 is performed to explore the origins of their different electrical properties.