Thermoelectric effects in silicene nanoribbons
Thermoelectric effects in silicene nanoribbons
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DOI：
10.1103/physrevb.88.115404
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发表时间：
2013-07
影响因子：
3.7
通讯作者：
K. Zberecki;M. Wierzbicki;J. Barna's;R. Świrkowicz
中科院分区：
文献类型：
--
作者：
K. Zberecki;M. Wierzbicki;J. Barna's;R. Świrkowicz
用从头算方法研究了锯齿形边缘硅烯纳米带的输运系数和热电系数（包括自旋热电势）。这种纳米带的局部自旋密度揭示了边缘磁性。像在石墨烯中一样，人们发现反铁磁和铁磁有序，其中一边的自旋极化分别与另一边的自旋极化反平行或平行。热电性能，特别是塞贝克系数，显着依赖于电子能带结构，并增强费米能级在能隙中。然而，这些热电性能显着降低时，声子贡献的热导包括在内。这种声子的贡献已经用两种不同的方法进行了数值计算。从反铁磁态到铁磁态的转变导致大的磁阻和相当大的磁热电势。反平行配置的热电参数，当自旋极化在纳米晶体的左部分是相反的，在右部分，也进行了分析。
Transport and thermoelectric coefficients (including also spin thermopower) of silicene nanoribbons with zigzag edges are investigated by {\it ab-initio} numerical methods. Local spin density of such nanoribbons reveals edge magnetism. Like in graphene, one finds antiferromagnetic and ferromagnetic ordering, with spin polarization at one edge antiparallel or parallel to that at the other edge, respectively. Thermoelectric properties, especially the Seebeck coefficient, significantly depend on the electronic band structure and are enhanced when the Fermi level is in the energy gap. However, these thermoelectric properties are significantly reduced when the phonon contribution to the heat conductance is included. This phonon contribution has been calculated numerically by two different methods. Transition from antiferromagnetic to ferromagnetic states leads to a large magnetoresistance as well as to a considerable magnetothermopower. Thermoelectric parameters in the antiparallel configuration, when spin polarization in the left part of the nanoribbon is opposite to that in the right part, are also analyzed.