2014/03/14 by S. J. S. da Silva, A. C. Seridonio, da Silva, S. J. S. +5
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Graphene research and applications #Quantum and electron transport phenomena #Strongly Correlated Electrons (cond-mat.str-el) #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.1403.3575
openalex publication_date 2014/03/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate theoretically nonequilibrium quantum transport in a quantum dot attached to a Majorana bound state. Our approach is based on the Keldysh Green's function formalism, which allows us to investigate the electric current continuously from the zero-bias limit up to the large bias regime. In particular, our findings fully agree with previous results in the literature that calculate transport using linear response theory (zero-bias) or the master equation (high bias). Our I-V curves reveal a characteristic slope given by I=(G0/2)V in linear response regime, where G0 is the ballistic conductance e2/h as predicted in Phys. Rev. B 84, 201308(R) (2011). Deviations from this behavior is also discussed when the dot couples asymmetrically to both left and right leads. The differential conductance obtained from the left or the right currents can be larger or smaller than G0/2 depending on the strength of the coupling asymmetry. In particular, the standard conductance derived from the Landauer-Büttiker equation in linear response regime does not agree with the full nonequilibrium calculation, when the two leads couple asymmetrically to the quantum dot. We also compare the current through the quantum dot coupled to a regular fermionic (RF) zero-mode or to a Majorana bound state (MBS). The results differ considerably for the entire bias voltage range analyzed. Additionally, we observe the formation of a plateau in the characteristic I-V curve for intermediate bias voltages when the dot is coupled to a MBS. Thermal effects are also considered. We note that when the temperature of the reservoirs is large enough both RF and MBS cases coincide for all bias voltages.