Superlattice nanowire heat engines with direction-dependent power output and heat current

• Published in: Physica. E, Low-dimensional systems & nanostructures Vol. 115; p. 113671
• Main Authors: Kuo, David M.T., Chang, Yia-Chung
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2020
• Subjects: Heat diode; Heat engine; Quantum dots; Superlattice nanowires; Heat diode; Heat engine; Quantum dots; Superlattice nanowires
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2019.113671

Heat engines (HEs) made of low dimensional structures offer promising applications in energy harvesting due to their reduced phonon thermal conductance. Many efforts have been devoted to the design of HEs made of quantum-dot (QD) superlattice nanowire (SLNW), but only SLNWs with uniform energy levels in QDs were considered. Here we propose a HE made of SLNW with staircase-like QD energy levels. The asymmetrical alignment of energy levels of quantum dots embedded in nanowires can be controlled to allow resonant electron transport under forward temperature bias, while they are in off-resonant regime under reverse temperature bias. Under such a mechanism, the power output and efficiency of such a SLNW are better than SLNWs with uniform QD energy levels. The SLNW HE has direction-dependent power output and heat current. In addition, the HE has the functionality of a heat diode with impressive negative differential thermal conductance under open circuit condition. •Quantum-dot superlattice nanowires (SLNW) with a staircase-like alignment of quantum-dot (QD) energy levels are proposed.•The power output and efficiency of SLNW heat engine are better than SLNWs with uniform QD energy levels.•The SLNW heat engine has direction-dependent power output and heat current.•The SLNW heat engine has an impressive negative differential thermal conductance under open circuit condition.•The designcan give rise to a high efficiency and optimized power output for SLNW heat engines.