Utilizing COMSOL Wave Functions to Improve Microscopic Computations for Double-Quantum-Dot Spin Qubit

In microscopic computations for double-quantum dot spin qubits, the Heitler-London (HL) and Hund-Mulliken (HM) approximations are commonly used. Our study assesses the exchange interaction between triplet and singlet states within a coupled double quantum dots (DQDs) near a (Si/SiO2) interface, employing COMSOL Multiphysics wave functions. We utilize two different models for the DQDs potential based on the inter-dot distance (d). These computations are conducted within a specific area of interest, considering various potentials. Our results are compared to scenarios where Fock-Darwin (FD) states are used and the solution to a one-dimensional(1D) Schrödinger equation is precisely known. Our findings demonstrate the efficiency of the employed technique and provide valuable insights into the reliability and accuracy of the chosen computational strategy.