Cao Zhan, Fang Tie-Feng, He Wan-Xiu, Luo Hong-Gang
Center for Interdisciplinary Studies and Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000, People's Republic of China.
J Phys Condens Matter. 2017 Apr 26;29(16):165302. doi: 10.1088/1361-648X/aa62d0. Epub 2017 Feb 24.
A quantum dot formed in a suspended carbon nanotube exposed to an external magnetic field is predicted to act as a thermoelectric unipolar spin battery which generates pure spin current. The built-in spin flip mechanism is a consequence of the spin-vibration interaction resulting from the interplay between the intrinsic spin-orbit coupling and the vibrational modes of the suspended carbon nanotube. On the other hand, utilizing thermoelectric effect, the temperature difference between the electron and the thermal bath to which the vibrational modes are coupled provides the driving force. We find that both magnitude and direction of the generated pure spin current are dependent on the strength of spin-vibration interaction, the sublevel configuration in dot, the temperatures of electron and thermal bath, and the tunneling rate between the dot and the pole. Moreover, in the linear response regime, the kinetic coefficient is non-monotonic in the temperature T and it reaches its maximum when [Formula: see text] is about one phonon energy. The existence of a strong intradot Coulomb interaction is irrelevant for our spin battery, provided that high-order cotunneling processes are suppressed.
预测在暴露于外部磁场的悬浮碳纳米管中形成的量子点可作为产生纯自旋电流的热电单极自旋电池。内置的自旋翻转机制是本征自旋 - 轨道耦合与悬浮碳纳米管振动模式之间相互作用所产生的自旋 - 振动相互作用的结果。另一方面，利用热电效应，电子与振动模式所耦合的热库之间的温差提供了驱动力。我们发现，所产生的纯自旋电流的大小和方向均取决于自旋 - 振动相互作用的强度、量子点中的子能级构型、电子和热库的温度以及量子点与电极之间的隧穿速率。此外，在线性响应区域，动力学系数在温度(T)中是非单调的，并且当([公式：见原文])约为一个声子能量时达到最大值。只要高阶共隧穿过程受到抑制，强量子点内库仑相互作用的存在与我们的自旋电池无关。
