Jiangsu Laboratory of Advanced Functional Materials, College of Physics and Engineering, Changshu Institute of Technology, Changshu, People's Republic of China.
Nanotechnology. 2011 Jun 3;22(22):225201. doi: 10.1088/0957-4484/22/22/225201. Epub 2011 Apr 1.
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 10π(2)k(B)(2)/(3e(2)). 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.
我们研究了嵌入在每个臂中的量子点的 Aharonov-Bohm (AB) 干涉仪的热电效应，其中考虑了每个 QD 中电子之间的内库仑相互作用。使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与传输谱中 Fano 线形状相关的分子态时，塞贝克系数和洛伦兹数可以得到强烈增强，这是由于键合和反键合分子态之间的量子干涉效应。研究发现，在存在强内库仑相互作用的情况下，热电效应在两组电导峰之间得到增强——原因是在库仑阻塞 regime 中出现了传输节点。在这种情况下，洛伦兹数的最大值接近 10π(2)k(B)(2)/(3e(2))。在没有声子热导的情况下，其无量纲系数 ZT 在室温下接近 2，因此在某些情况下可以用作高效固态热电转换器件。
