Topological Insulators in Quantum Heat Engines

We investigate the effects of using a topological insulator (TI) in quantum heat engines (QHEs). Stanene, a two-dimensional topological insulator with intrinsic spin-orbit interaction (SOI), in an external electric field () is... [ view full abstract ]

We investigate the effects of using a topological insulator (TI) in quantum heat engines (QHEs). Stanene, a two-dimensional topological insulator with intrinsic spin-orbit interaction (SOI), in an external electric field () is chosen as a working substance of QHEs. Our primary studies show that band gap of stanene is controllable by the external electric field and the combination of  SOI and   leads to topological phase transition (TPT). We continue our investigation by analyzing the net work produced in two types of QHEs, quantum Otto cycle (QOC) and non-adiabatic cycle. According to the results in QOC, using TI and choosing an appropriate range of  lead to a broad region of positive work compare with the previous cycles. TPT significantly observe in both work and efficiency plots as a kink. This makes possible to probe the TPT. The wide region of positive work is more remarkable in non-adiabatic cycle, the work is done for all values of the electric field, but there is no sign of TPT in efficiency plot. In this cycle, by limiting the energy band of stanene to electronic levels work and efficiency go to zero exactly at TPT point. This means in topological phase of working substance work is done but it gets zero at TPT and keeps this value in trivial phase. It is a good signature to identify the TPT. Our results also predict that the proposed cycles are experimentally realizable at room temperature with suitable magnitudes of the electric field.