Chin. Phys. B, 2022, Vol. 31(7): 077202    DOI: 10.1088/1674-1056/ac4f53
 CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES Prev   Next

# Current spin polarization of a platform molecule with compression effect

Zhi Yang(羊志)1, Feng Sun(孙峰)1, Deng-Hui Chen(陈登辉)1, Zi-Qun Wang(王子群)2, Chuan-Kui Wang(王传奎)1, Zong-Liang Li(李宗良)1,†, and Shuai Qiu(邱帅)1,‡
1 Shandong Key Laboratory of Medical Physics and Image Processing&Shandong Provincial Engineering and Technical Center of Light Manipulations, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China;
2 Zao Zhuang University, Zao Zhuang 277160, China
Abstract  Using the first-principles method, the spin-dependent transport properties of a novel platform molecule containing a freestanding molecular wire is investigated by simulating the spin-polarized scanning tunneling microscope experiment with Ni tip and Au substrate electrodes. Transport calculations show that the total current increases as the tip gradually approaches to the substrate, which is consistent with the conductance obtained from previous experiment. More interestingly, the spin polarization (SP) of current modulated by compression effect has the completely opposite trend to the total current. Transmission analyses reveal that the reduction of SP of current with compression process originates from the promotion of spin-down electron channel, which is controlled by deforming the molecule wire. In addition, the density of states shows that the SP of current is directly affected by the organic-ferromagnetic spinterface. The weak orbital hybridization between the Ni tip and propynyl of molecule results in high interfacial SP, whereas the breaking of the C $\equiv$ C triple of propynyl in favor of the Ni-C-C bond induces the strong orbital hybridization and restrains the interfacial SP. This work proposes a new way to control and design the SP of current through organic-ferromagnetic spinterface using functional molecular platform.
Keywords:  molecular spintronics      spin-dependent transport      spin polarization      single-molecule junctions
Received:  16 December 2021      Revised:  13 January 2022      Accepted manuscript online:  27 January 2022
 PACS: 72.25.-b (Spin polarized transport) 75.47.-m (Magnetotransport phenomena; materials for magnetotransport) 85.75.-d (Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields)
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos. 11974217 and 11874242) and the Natural Science Foundation of Shandong Province, China (Grant No. ZR2018MA037).
Corresponding Authors:  Zong-Liang Li, Shuai Qiu     E-mail:  lizongliang@sdnu.edu.cn;shuaiqiu@sdnu.edu.cn