Engineering C₆₀||B₆₀ Heterostructure for High Performance Electro-Optic Response: A Theoretical Performance Study

Abstract

The rational design of materials with giant, electronically dominated nonlinear optical (NLO) responses is a central goal in modern photonics. This comprehensive first-principles study introduces a novel C 60 ||B 60 van der Waals heterostructure, revealing its potential as a paradigmshifting electro-optic (EO) material. Calculations based on many-body perturbation theory predict a colossal second-order NLO susceptibility, which translates to an unprecedented EO coefficient approaching 30,000 pm/V-three orders of magnitude larger than that of benchmark lithium niobate. This giant response is shown to be over 99.9% electronic in origin, enabling ultrafast switching capabilities. The origin of this performance is traced to the unique electronic environment engineered at the interface. The direct-gap semiconductor (Eg ≈ 0.87 eV) possesses a profoundly anisotropic ground state, evidenced by a record dielectric anisotropy (ε yy /ε zz ≈ 65). Maximally-localized Wannier function analysis provides direct real-space evidence for 58 symmetry-breaking interfacial electronic states within the van der Waals gap. These highly polarizable hybrid orbitals, which exhibit long quasiparticle lifetimes, are identified as the definitive microscopic source of the immense EO effect. These findings establish fullerene heterostructures as a revolutionary platform for nonlinear photonics and provide a clear blueprint for the quantum-mechanical design of next-generation functional 2D materials.