In recent years, new spin-dependent thermal effects have been discovered in ferromagnets, stimulating a growing interest in spin caloritronics, a field that exploits the interaction between spin and heat currents^1,2. Amongst the most intriguing phenomena is the spin Seebeck effect^3,4,5, in which a thermal gradient gives rise to spin currents that are detected through the inverse spin Hall effect^6,7,8. Non-magnetic materials such as graphene are also relevant for spin caloritronics, thanks to efficient spin transport^9,10,11, energy-dependent carrier mobility and unique density of states^12,13. Here, we propose and demonstrate that a carrier thermal gradient in a graphene lateral spin valve can lead to a large increase of the spin voltage near to the graphene charge neutrality point. Such an increase results from a thermoelectric spin voltage, which is analogous to the voltage in a thermocouple and that can be enhanced by the presence of hot carriers generated by an applied current^14,15,16,17. These results could prove crucial to drive graphene spintronic devices and, in particular, to sustain pure spin signals with thermal gradients and to tune the remote spin accumulation by varying the spin-injection bias.

近年来，在铁磁体中发现了新的自旋相关的热效应，激发了人们对自旋量热电子学的兴趣，自旋量​​热电子学利用了自旋和热流^1,2之间的相互作用。其中最引人入胜的现象是自旋塞贝克效应^3,4,5，其中热梯度会产生通过逆自旋霍尔效应^6,7,8检测到的自旋电流。非磁性材料（例如石墨烯）也与自旋量热电子学相关，这要归功于高效的自旋输运^9,10,11，能量依赖的载流子迁移率和独特的态密度^12,13。在这里，我们提出并证明，石墨烯横向自旋阀中的载流子热梯度会导致靠近石墨烯电荷中性点的自旋电压大幅增加。这种增加是由热电自旋电压引起的，该热电自旋电压类似于热电偶中的电压，并且可以通过存在由施加的电流^14,15,16,17产生的热载流子来增强。这些结果可能证明对驱动石墨烯自旋电子器件至关重要，尤其是维持具有热梯度的纯自旋信号，以及通过改变自旋注入偏压来调节远程自旋累积。