First principles study on lattice vibration and electrical properties of layered perovskite Sr2M2O7 (M = Nb, Ta)<xref rid="cpb_27_8_086104_fn1" ref-type="fn">*</xref><fn id="cpb_27_8_086104_fn1"><label>*</label>Project supported by the National Natural Science Foundation of China (Grant No. 51672220), the 111 Program of the Ministry of Education of China (Grant No. B08040), the National Defense Science Foundation (Grant No. 32102060303), the Xi’an Science and Technology Foundation, the Shaanxi Provincial Science Foundation and the Gaofeng Project of Northwestern Polytechnical University, China (Grant No. 17GH020824).</fn>

First principles study on lattice vibration and electrical properties of layered perovskite Sr₂M₂O₇ (M = Nb, Ta)**

Project supported by the National Natural Science Foundation of China (Grant No. 51672220), the 111 Program of the Ministry of Education of China (Grant No. B08040), the National Defense Science Foundation (Grant No. 32102060303), the Xi’an Science and Technology Foundation, the Shaanxi Provincial Science Foundation and the Gaofeng Project of Northwestern Polytechnical University, China (Grant No. 17GH020824).

Liu Xing^†, Fan Hui-Qing^‡

(color online) The charge relation of volume, polarization, and bond length with pressure increase.