Theoretical Study of the Quantum Capacitance of Monolayer WSe2 under the Influence of the Temperature, External Electric Field and Zeeman Field

This study investigates the quantum capacitance ( $${{C}_{Q}}$$ ) of a monolayer $${\text{WS}}{{{\text{e}}}_{2}}$$ under the influence of an electric field $${{\Delta }_{z}}$$ and spin/valley Zeeman fields $${{M}_{z}}$$ and $${{M}_{{v}}}$$ . The results demonstrate that at low temperatures (10, 30 K), the electric field and Zeeman fields eliminate the abrupt sharp jump in $${{C}_{Q}}$$ , leading to a series of smoother, gradual steps. This behavior arises from the increased number of sublevels in the energy structure of $${\text{WS}}{{{\text{e}}}_{2}}$$ , induced by external fields. In contrast, at room temperature (approximately 300 K), the thermodynamic effects dominate, resulting in a smooth $${{C}_{Q}}$$ curve, regardless of the presence of electric or Zeeman fields. The dip in $${{C}_{Q}}$$ within the energy gap region remains a characteristic feature of $${\text{WS}}{{{\text{e}}}_{2}}$$ , reflecting its semiconductor nature with a band gap modulated by $${{\Delta }_{z}}$$ . These findings highlight the pivotal role of external fields in tuning the quantum capacitance of $${\text{WS}}{{{\text{e}}}_{2}}$$ , offering potential insights for the development of advanced nanoelectronic and spintronic devices based on two-dimensional materials.