Tunable Thermal Switching via DNA-Based Nano Devices

DNA has a well-defined structural transition -- the denaturation of its double-stranded form into two single strands -- that strongly affects its thermal transport properties. We show that, according to a paradigmatic model of DNA denaturation, one can engineer DNA ``heattronic'' devices that have a rapidly increasing thermal conductance over a narrow temperature range across the denaturation transition ($\sim$350 K). The origin of this rapid increase of conductance, or ``switching,'' is the softening of the lattice and suppression of nonlinear effects as the temperature crosses the transition temperature and DNA denatures. Most importantly, we demonstrate that DNA nanojunctions have a broad range of thermal tunability due to varying the sequence and length, and exploiting the underlying nonlinear behavior. We discuss the role of disorder in the base sequence, as well as the relation to genomic DNA. These results set the basis for developing thermal devices out of materials with nonlinear structural dynamics, as well as understanding the underlying mechanisms of DNA denaturation.