Highly efficient quantum heat engine operating at maximum power in the α -T 3 lattice

The α−T3 lattice, an interpolation of graphene's honeycomb lattice and the dice lattice, has drawn a lot of attention. Herein, the thermoelectric properties of the α−T3 lattice based junction are investigated. The parameter φ and the gate voltage Vg can be utilized for adjusting thermoelectric properties. Without the mass term Δ, the efficiency at maximum power η is relatively low, similar to two-dimensional graphene. When Δ is introduced, the initially flat band warps and disperses, resulting in a band gap between the distorted flat band and the conduction (valence) band. In this case, the maximum power and η are both greatly enhanced and are adjustable by Vg and φ. With high output power, η can be higher than 0.3 Carnot efficiency. As a result, it is suggested that the α−T3 lattice will be utilized to create a highly efficient quantum heat engine.