Magnetothermoelectric transport properties of multiterminal graphene nanoribbons
Magnetothermoelectric transport properties of multiterminal graphene nanoribbons
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多端石墨烯纳米带的磁热电传输特性
DOI：
10.1103/physrevb.93.245432
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发表时间：
2016
影响因子：
3.7
通讯作者：
Sun Qing-Feng
中科院分区：
文献类型：
--
作者：
Wei Miao-Miao;Zhang Ying-Tao;Guo Ai-Min;Liu Jian-Jun;Xing Yanxia;Sun Qing-Feng
研究了石墨烯纳米带中的Peltier效应和Ettingshausen效应，前者是电荷电流沿纵向沿着产生热流，后者是纵向电荷电流沿纵向产生横向热流.借助于非平衡绿色函数和Landauer-Büttiker形式，得到了Peltier系数和Ettingshausen系数。我们发现，开尔文关系总是有效的纵向热电输运，即，with the temperature温度and Seebeck塞贝克coefficient系数.相反，对于横向磁热电输运，开尔文关系破裂，并且通常具有能斯特系数.在弱磁场区，Ettingshausen效应强烈依赖于器件参数。当费米能接近狄拉克点时，半导体扶手椅型石墨烯纳米粒子的Ettingshausen效应比金属扶手椅型石墨烯纳米粒子的Ettingshausen效应强得多。当远离Dirac点时，Ettingshausen系数在零附近振荡。当在强磁场下时，与器件参数无关，仅在狄拉克点附近膨胀。此外，对的依赖性可以通过缩放，对于三端系统和四端系统具有峰值。我们还研究了障碍对Ettingshausen效应的影响。无论磁场强度如何，都对中等无序散射具有鲁棒性。另外，在强磁场中，附加有规则的振荡结构可以引起无序。
The Peltier effect and the Ettingshausen effect are investigated in graphene nanoribbons, where charge current produces heat current along the longitudinal direction in the former case, and longitudinal charge current generates transverse heat current in the latter case. With the aid of the nonequilibrium Green's function and the Landauer-Büttiker formalism, the Peltier coefficientand the Ettingshausen coefficientare obtained. We found that the Kelvin relation is always valid for the longitudinal thermoelectric transport, i.e.,, withthe temperature andthe Seebeck coefficient. In contrast, for transverse magnetothermoelectric transport, the Kelvin relation breaks down andusually, withthe Nernst coefficient. In the region of weak magnetic field, the Ettingshausen effect depends strongly on device parameters. When the Fermi energyis close to the Dirac point, the Ettingshausen effect of the semiconducting armchair graphene nanoribbon is much stronger than that of the metallic one. Whenis far away from the Dirac point, the Ettingshausen coefficientoscillates around zero. When under a strong magnetic field,is independent of the device parameters and swells only near the Dirac point. Further, the dependence ofoncan be scaled by, with a peak value offor the three-terminal system andfor the four-terminal system. We also study the impact of disorder on the Ettingshausen effect. Regardless of the magnetic field strength,is robust against moderate disorder scattering. In addition, in the strong magnetic field,with additional regular oscillating structure can be caused by disorder.