Effect of excess charge carriers and fluid medium on the magnitude and sign of the Casimir-Lifshitz torque
Last year, we reported a perturbative theory of the Casimir-Lifshitz torque between planar biaxially anisotropic materials in the retarded limit [Thiyam et al., Phys. Rev. Lett. 120, 131601 (201810.1103/PhysRevLett.120.131601)], which is applied here to study the change in sign and magnitude of the torque with separation distance in biaxial black phosphorus having excess charge carriers. The study