Engineering C60‖B60 heterostructure for high performance electro-optic response: a theoretical performance study

Abstract

The rational design of materials with electronic and nonlinear optical (NLO) response performance is a central goal in modern photonics. This comprehensive first-principles study introduces a novel C₆₀‖B₆₀ van der Waals heterostructure, revealing its potential as a theoretical performance boundary, as an electro-optical (EO) materials. 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⁻¹, three orders of magnitude larger than that of benchmark lithium niobate. These predictions under ideal conditions are 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 (E_g ≈ 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 predicted highly polarizable hybrid orbitals, which exhibit long quasiparticle lifetimes, are identified as the definitive microscopic source of the immense EO effect. These predictions establish this heterostructure as a platform for nonlinear photonics and provide clear guidelines for the quantum-mechanical design of next-generation functional 2D materials.