Casimir-Lifshitz torque between cholesteric DNA stacks
Phys. Rev. B 113, 085412 – Published 9 February, 2026
DOI: https://doi.org/10.1103/3l81-jk8q
Abstract
We theoretically investigate the Casimir-Lifshitz torque between two stacks of cholesteric DNA embedded in water and surrounded by silica substrates. We utilize the spiral staircase model combined with the Rayleigh method to describe the geometric structure of DNA films. It is found that for a specific nucleotide base pairing, the adenine-thymine (AT)10 oligomer, the torque amplitude exceeds four times that predicted by the bulk dielectric function model, and the finite-thickness effect remains significant even at distances two orders of magnitude smaller than the DNA stacking thickness. This highlights the need for realistic modeling of the DNA liquid crystal based on the proper dielectric function and geometry. These results may have applications in the emerging field of DNA-based nanotechnology.
