Thermoelectric Effect in a Correlated Quantum Dot Side-Coupled to Majorana Bound States

• Main Authors: Feng Chi, Zhen-Guo Fu, Jia Liu, Ke-Man Li, Zhigang Wang, Ping Zhang
• Format: Article
• Language: English
• Published: SpringerOpen 2020-04-01
• Series: Nanoscale Research Letters
• Subjects: Thermoelectric effect; Quantum dot; Majorana bound states; Thermopower
• Online Access: http://link.springer.com/article/10.1186/s11671-020-03307-y

Abstract We theoretically study the thermoelectric effect in a hybrid device composed by a topological semiconducting nanowire hosting Majorana bound states (MBSs) and a quantum dot (QD) connected to the left and right non-magnetic electrodes held at different temperatures. The electron-electron Coulomb interactions in the QD are taken into account by the non-equilibrium Green’s function technique. We find that the sign change of the thermopower, which is useful for detecting the MBSs, will occur by changing the QD-MBS hybridization strength, the direct overlap between the MBSs at the opposite ends of the nanowire, and the system temperature. Large value of 100% spin-polarized or pure spin thermopower emerges even in the absence of Zeeman splitting in the QD or magnetic electrodes because the MBSs are coupled to electrons of only one certain spin direction in the QD due to the chiral nature of the Majorana fermions. Moreover, the magnitude of the thermopower will be obviously enhanced by the existence of MBSs.