Liu Qing-Bo, Wu Dan-Dan, Fu Hua-Hua
School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Phys Chem Chem Phys. 2017 Oct 11;19(39):27132-27139. doi: 10.1039/c7cp05621d.
By using the first-principle calculations combined with the non-equilibrium Green's function approach, we have studied spin caloritronic properties of graphene nanoribbons (GNRs) with different edge defects. The theoretical results show that the edge-defected GNRs with sawtooth shapes can exhibit spin-dependent currents with opposite flowing directions by applying temperature gradients, indicating the occurrence of the spin-dependent Seebeck effect (SDSE). The edge defects bring about two opposite effects on the thermal spin currents: the enhancement of the symmetry of thermal spin-dependent currents, which contributes to the realization of pure thermal spin currents, and the decreasing of the spin thermoelectric conversion efficiency of the devices. It is fortunate that applying a gate voltage is an efficient route to optimize these two opposite spin thermoelectric properties towards realistic device applications. Moreover, due to the existence of spin-splitting band gaps, the edge-defected GNRs can be designed as spin-dependent Seebeck diodes and rectifiers, indicating that the edge-defected GNRs are potential candidates for room-temperature spin caloritronic devices.
通过结合第一性原理计算和非平衡格林函数方法，我们研究了具有不同边缘缺陷的石墨烯纳米带（GNRs）的自旋热电子学性质。理论结果表明，锯齿形边缘缺陷的GNRs通过施加温度梯度可以表现出具有相反流动方向的自旋相关电流，这表明发生了自旋相关塞贝克效应（SDSE）。边缘缺陷对热自旋电流产生两种相反的影响：增强热自旋相关电流的对称性，这有助于实现纯热自旋电流；以及降低器件的自旋热电转换效率。幸运的是，施加栅极电压是优化这两种相反的自旋热电性质以实现实际器件应用的有效途径。此外，由于存在自旋分裂带隙，边缘缺陷的GNRs可以被设计为自旋相关塞贝克二极管和整流器，这表明边缘缺陷的GNRs是室温自旋热电子器件的潜在候选材料。
