The role of Coulomb interaction in thermoelectric effects of an Aharonov–Bohm interferometer
The role of Coulomb interaction in thermoelectric effects of an Aharonov–Bohm interferometer
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DOI：
10.1088/0957-4484/22/22/225201
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发表时间：
2011-06
期刊：
影响因子：
3.5
通讯作者：
Yu-Shen Liu;Debao Zhang;Xifeng Yang;Jinlong Feng
中科院分区：
文献类型：
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作者：
Yu-Shen Liu;Debao Zhang;Xifeng Yang;Jinlong Feng
我们研究了阿哈罗诺夫-玻姆 (AB) 干涉仪的热电效应，该干涉仪的每个臂中都嵌入了一个量子点 (QD)，其中考虑了每个 QD 中电子之间的点内库仑相互作用。利用格林函数方法和运动方程（EOM）技术，我们发现当化学势扫过透射光谱中与法诺线形相关的分子态时，由于键合和反键合分子态之间的量子干涉效应，塞贝克系数和洛伦兹数会大大增强。研究发现，在存在强点内库仑相互作用的情况下，两组电导峰之间的热电效应会增强，原因是在库仑封锁状态下形成了传输节点。在这种情况下，洛伦兹数的最大值接近10π2kB2/(3e2)。在没有声子热导的情况下，其热电转换效率（用品质因数 ZT 描述）在室温下接近 2。因此，在一定条件下可以作为高效的固态热电转换器件。
We investigate the thermoelectric effects of an Aharonov–Bohm (AB) interferometer with a quantum dot (QD) embedded in each of its arms, where the intra-dot Coulomb interaction between electrons in each QD is taken into account. Using Green’s function methods and the equation of motion (EOM) technique, we find that the Seebeck coefficient and Lorenz number can be strongly enhanced when the chemical potential sweeps the molecular states associated with the Fano line-shapes in the transmission spectra, due to quantum interference effects between the bonding and antibonding molecular states. It is found that enhancement of the thermoelectric effects occurs between the two groups of conductance peaks in the presence of strong intra-dot Coulomb interaction—the reason being that a transmission node is developed in the Coulomb blockade regime. In this case, the maximum value of the Lorenz number approaches 10π2kB2/(3e2). Its thermoelectric conversion efficiency in the absence of phonon thermal conductance, described by the figure of merit ZT, approaches 2 at room temperature. Therefore, it may be used as a high-efficiency solid-state thermoelectric conversion device under certain circumstances.