摘要
Heat current exchanged between a two-level quantum dot(QD) and a phonon reservoir coupled to it is studied within the nonequilibrium Green's function method. We consider that the QD is connected to the left and right ferromagnetic leads. It is found that the negative differential of the heat generation(NDHG) phenomenon,i.e.,the intensity of the heat generation decreases with increasing bias voltage,is obviously enhanced as compared to that in single-level QD system. The NDHG can emerge in the absence of the negative differential conductance of the electric current,and occurs in different bias voltage regions when the magnetic moments of the two leads are arranged in parallel or antiparallel configurations. The characteristics of the found phenomena can be understood by examining the change of the electron number on the dot.
Heat current exchanged between a two-level quantum dot(QD) and a phonon reservoir coupled to it is studied within the nonequilibrium Green’s function method. We consider that the QD is connected to the left and right ferromagnetic leads. It is found that the negative differential of the heat generation(NDHG) phenomenon,i.e.,the intensity of the heat generation decreases with increasing bias voltage,is obviously enhanced as compared to that in single-level QD system. The NDHG can emerge in the absence of the negative differential conductance of the electric current,and occurs in different bias voltage regions when the magnetic moments of the two leads are arranged in parallel or antiparallel configurations. The characteristics of the found phenomena can be understood by examining the change of the electron number on the dot.
基金
Supported by the National Natural Science Foundation of China under Grant No.61274101
the Liaoning Excellent Talents Programand(LJQ2013118)
the Foundation of State Key Laboratory of Explosion Science and Technology of Beijing Institute of Technology(KFJJ14-08M)
