Phononic heat transport and pumping in systems with long-ranged interactions

BERAHA N; CARUSELA M. F; SOBA A

Buenos Aires

Conferencia; 27th IUPAP International Conference on Statistical Physics, StatPhys27.; 2019

We propose a microscopic model to investigate the energy transport in a lowdimensional nanomechanical system. The model consists of a one dimensionalchain composed by arrays of oscillators with different structures. The segmentsare connected through short-ranged time-dependent nanomechanical perturba-tions. The atoms constituting the different regions are harmonically and bidi-rectionally coupled. The strength of the interaction between two atoms decaysas a power α of the inverse of their distance. The ends of the whole chain areshort-range coupled to thermal reservoirs at different temperatures. The atomsare also in the presence of a substrate whose interaction, for low temperatures,is modeled up to first order with an harmonic on-site potential. Following thenon-equilibrium Green?s function formalism, we study numerically the energytransport, analyzing the pumping of heat towards/from reservoirs. We explorethe existence of different energy transport regimes (e.g. diffusion, heat pump,heat engine) as a function of temperature gradients, size of the system, fre-quency, intensity of the mechanical modulation and α. We discuss the effectof the range parameter on blocking or enabling ?heat channels?. On the otherhand, for higher temperatures the interaction with the substrate is modeledwith an-harmonic potential which introduces new sources of scattering. In thiscase the study is based on molecular dynamics simulations. We discussed theresults obtained for the two temperature limits.