Stefano Iubini — Istituto dei Sistemi Complessi CNR - Sesto Fiorentino #
Thermodynamics of photonic nonlinear Aharonov-Bohm cages #
We investigate the thermodynamic and non-equilibrium properties of an open nonlinear diamond lattice under the influence of a uniform magnetic field. The chain exhibits two dispersive bands and one zero-energy flat band. By fine-tuning the magnetic flux, all three Bloch bands turn flat, resulting in Aharonov-Bohm caging and the total suppression of particle and energy currents. The equilibrium phase diagram is obtained as function of the flux. By driving the system at the boundaries with two thermostats, we study the transport of norm and energy across the system for different flux values and nonlinear strengths. For weak nonlinearity, the caging condition turns the system into an insulator, while the system is ''metallic'' for all other flux values. For intermediate nonlinear strength instead, the system behaves as a conductor for any flux value. However, in this regime the caging condition enhances Seebeck coefficient and the figure of merit, improving the thermoelectric features of the chain. These results highlight the magnetic flux as a versatile control parameter for effectively tuning the thermodynamic and transport signatures of the system.