Theoretical investigation on nonequilibrium Peltier effect in quantum dots coupled to Majorana bound states

Abstract We theoretically investigate the nonequilibrium Peltier effect in a system comprises of quantum dots (QDs) side-coupled to Majorana bound states (MBSs), explicitly contrasting it against both topologically trivial Andreev bound states (ABSs) and a regular fermionic system—realized as a T-shaped double-QD structures (TDQDs). Using the non-equilibrium Green’s function method, we calculate the charge current, entropy current, and the nonlinear Peltier coefficient (Π) under finite bias. We report a bias-tunable thermoelectric fingerprint of the MBSs: in the moderate and strong nonlinear regimes ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>e</mml:mi> <mml:mi>V</mml:mi> <mml:mo>≳</mml:mo> <mml:mi mathvariant="normal">Γ</mml:mi> </mml:mrow> </mml:math> ) where V is the bias voltage and Γ the line-width function, the number and position of the zero-crossing points in Π for the MBS system are fundamentally different from those of both the regular fermionic TDQDs and the ABSs. These divergences stem from the interplay between the extended bias window and the Majorana-induced zero-energy resonance, which enables a unique bias-controlled sign reversal of the heat flow. Furthermore, in a hybrid double-QDs architecture where one dot is coupled to a MBS (M-TDQDs), we find that topological particle-hole symmetry breaking dominates the transport in the strong nonlinear regime. This mechanism effectively stabilizes the thermoelectric response, rendering it intrinsically robust against conventional Fano interference. Our findings demonstrate that the nonlinear Peltier effect may serve as a robust, complementary probe for distinguishing MBSs from trivial fermionic and Andreev states, offering a new scheme for energy flow control in quantum devices.