Quantum coherent control of nonlinear thermoelectric transport in a triple-dot Aharonov-Bohm heat engine

Abstract

We investigate the role of quantum coherence and higher harmonics resulting from multiple-path interference in nonlinear thermoelectricity in a two-terminal triangular triple-dot Aharonov-Bohm (AB) interferometer. We quantify the trade-off between efficiency and power in the nonlinear regime of our simple setup comprising three non-interacting quantum dots (two connected to two biased metallic reservoirs) placed at the vertex of an equilateral triangle, and a magnetic flux $\Phi$ pierces it perpendicularly. For a spatially symmetric setup, we achieve optimal efficiency and power output when the inter-dot tunneling strength is comparable to the dot-lead coupling, AB phase $\varphi =\pi /2$. Our analysis reveals that the presence of higher harmonics is necessary but not sufficient to achieve optimal power output. The maximal constructive interference represented by three close-packed resonance peaks of the unit transmission can enhance the power output ($P_{max}\sim 2.35\mathrm{fW}$) almost 3.5 times as compared to the case where only a single channel participates in the transport, and the corresponding efficiency is about $0.80{\eta }_c$ where ${\eta }_c$ is the Carnot efficiency. Geometric asymmetries and their effects on efficiency and power output are also investigated. An asymmetric setup characterized by the ratio of the coupling to the source and the drain terminals ($x$) can further enhance the maximum power output $P_{max}\sim 3.85\mathrm{fW}$ for $x=1.5$ with the same efficiency as that of the symmetric case. Our investigation reveals that the output power and efficiency are optimal in the wide-band limit. The power output is significantly reduced for the narrow-band case. On the other hand, disorder effects radically reduce the performance of the heat engine.

References in corpus (16)

• A note on symmetry reductions of the Lindblad equation: transport in constrained open spin chains
• Giant thermopower and figure of merit in single-molecule devices
• Quantum Thermodynamics: A Nonequilibrium Green's Functions Approach
• Finding the quantum thermoelectric with maximal efficiency and minimal entropy production at given power output
• Two path transport measurements on a triple quantum dot
• Thermoelectric efficiency of three-terminal quantum thermal machines
• Disorder and dephasing effect on electron transport through conjugated molecular wires in molecular junctions
• Efficiency bounds on thermoelectric transport in magnetic fields: The role of inelastic processes
• Thermoelectric efficiency of nanoscale devices in the linear regime
• Steady-state thermodynamics of non-interacting transport beyond weak coupling
• Nonlocal quantum heat engines made of hybrid superconducting devices
• A triangular triple quantum dot with tunable tunnel couplings
• Aharonov-Bohm oscillations in p-type GaAs quantum rings
• Entropy and information flow in quantum systems strongly coupled to baths
• Scanning probe-induced thermoelectrics in a quantum point contact
• Anomalous magnetotransport through reflection-symmetric artificial molecules

Cited by in corpus (7)

• A review on Aharonov-Bohm quantum machines: Thermoelectric heat engines and diodes
• Quantum coherence effects on inelastic thermoelectric devices: From diodes to transistors
• Coherent control of thermoelectric currents and noise in quantum thermocouples
• Thermoelectric performance of quantum dots embedded in an Aharonov-Bohm ring: a Pauli master equation approach
• Thermal junctions controlled with Aharonov-Bohm phases
• Quantum thermocouples: nonlocal conversion and control of heat in nanostructures
• Potential barriers are nearly-ideal quantum thermoelectrics at finite power output