Quantum capacitance of dressed monolayer jacutingaite Pt2HgSe3

To optimize next-generation electronic and quantum devices based on low-dimensional systems, accurately evaluating the total capacitance – particularly the quantum capacitance (QC) – is essential. In this study, we employ the Kane–Mele model alongside the Boltzmann transport approach to show how QC can be effectively tuned through topological phase transitions in monolayer jacutingaite (Pt${}_2$HgSe${}_3$) under the influence of static and dynamic electric fields. Remarkably, we find that QC is significantly enhanced when the system undergoes a transition from a quantum spin Hall insulator phase to a semimetallic phase. In contrast, QC is suppressed when the transition leads to a band insulator or quantum Hall insulator phase. We further explore how QC responds to variations in temperature and static electric field strength as a function of the applied dynamic electric field.