基于理想共振隧穿的三端量子点热机

A three-terminal quantum dot heat engine based on ideal resonant tunneling

由两个单能级量子点、一个腔和两个电子库耦合形成三端量子点热机模型.通过Landauer公式导出了热机的输出功率以及效率表达式,数值模拟出该热机功率与效率之间的性能特征图,确定了热机性能的优化范围.之后,在最大功率与最大效率作为优化目标下,分析了热漏和能级宽度对热机性能的影响.最后,讨论了在最大功率下对应的效率随卡诺效率变化的关系并且与CA效率进行了比较.研究表明:由于能级宽度和热漏的存在,该热机为一个不可逆热机,热机的效率和功率的特性为一个闭合曲线;由于存在热漏,热机效率和能级宽度的特性为非单调曲线;不考虑热漏和能级宽度,最大功率下的效率将大于CA效率.

In this paper, the model of a three-terminal quantum dot heat engine consists of two quantum dots with a single energy level, a cavity and two electron reservoirs is established. According to Landauer formula the expressions for the heat current, the output power and the efficiency are derived analytically. The performance characteristic curves of the output power versus the efficiency are plotted by numerical calculation. Moreover, the optimal performance parameters are determined. Then we optimize the output power and the efficiency respectively, the influence of the width of energy level and the heat leak on performance of the three-terminal thermoelectric heat engine is discussed. Lastly, the variation of the corresponding efficiency at the maximum power output with the Carnot efficiency between two reservoirs is discussed and the corresponding efficiency is compared with Carnot efficiency and CA efficiency. It is shown that this three-terminal heat engine is irreversible due to the existence of the width of energy level and the heat leak. Thus the curve of the power output versus the efficiency is a loop-shaped one. And due to the heat leak, the characteristics of the efficiency and the width of energy level is a non-monotone curve. The efficiency at the maximum power will be greater than the CA efficiency when the heat leak and the width of energy level are not taken into account.