Dual Negative Differential of Heat Generation in a Strongly Correlated Quantum Dot Side-Coupled to Majorana Bound States

We study theoretically the properties of local heat originated from energy exchange between electrons passing through a quantum dot (QD) coupled to a phonon bath. The dot is sandwiched between two normal metal leads and also side-coupled to Majorana bound states (MBSs) formed at opposite ends of a topological superconductor nanowire. We find that in addition to the negative differential of heat generation (NDHG) in the Coulomb blockade regime, another NDHG emerges near the leads' Fermi level due to the dot-MBS coupling. This dual NDHG effect is robust against the variation of intradot Coulomb interaction strength, and disappears if the QD is coupled to regular Fermions. Direct hybridization between the MBSs reduces their impacts on the electronic transport processes, and eliminates the dual NDHG effect. Our results show that the dual NDHG effect is quite efficient for inferring the existence of MBSs, and may remedy some limitations of the detection schemes relying on tunneling spectroscopy technique.

Automated summary

In this theoretical study, the generation of local heat originating from electron energy exchange in a quantum dot coupled to a phonon bath is investigated. It is found that in addition to negative differential heat generation in the Coulomb blockade regime, another effect occurs near the Fermi level of the leads due to dot-MBS coupling. The direct hybridization between MBSs reduces their impact on electronic transport processes and eliminates the dual negative differential heat generation effect. This study demonstrates the efficiency of the dual negative differential heat generation effect in inferring the presence of MBSs and potentially overcoming limitations of detection schemes based on tunneling spectroscopy technique.