Universal Scalings in Two-Dimensional Anisotropic Dipolar Excitonic Systems

Low-dimensional excitonic materials have inspired much interest owing to their novel physical and technological prospects. In particular, those with strong in-plane anisotropy are among the most intriguing but short of general analyses. We establish universal functional form anisotropic dispersion in small $k$ limit for 2D dipolar systems. While energy is linearly dispersed direction parallel dipole in-plane, perpendicular dispersionless up linear order, which can be explained by quantum interference effect interaction constituents 1D subsystems. The results a $E^{\sim0.5}$ scaling system density states predicts unique spectroscopic signatures including: (1) disorder-induced absorption linewidth, $W(\sigma)\sim\sigma^{2.8}$, $\sigma$ disorder strength, (2) temperature dependent $W(T)\sim T^{s+1.5}$, $s$ exponent environment spectral density, (3) out-of-plane angular $\theta$ dependence peak splittings spectra, $\Delta E(\theta)\propto\sin^2\theta$. These predictions confirmed quantitatively numerical simulations molecular thin films tubules.