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Swaraj Biswas

Publications and source records attributed to Swaraj Biswas.

2 recordsLinked to original sources

Correlated quasiperiodicity enables efficient thermoelectric energy conversion

We investigate a route to enhanced thermoelectric energy conversion in nanoscale systems by exploiting a correlated quasiperiodic energy landscape in a one-dimensional chain coupled to source and drain reservoirs. The considered modulation generates a highly non-uniform electronic transmission spectrum, providing favorable conditions for achieving a large thermoelectric figure of merit. By systematically tuning the incommensurability parameter, a variety of quasiperiodic configurations are explored, several of which yield high values of the figure of merit exceeding $2$. Electronic transport properties are evaluated within a tight-binding framework using the non-equilibrium Green's function formalism, while the thermoelectric coefficients, including electrical conductance, Seebeck coefficient, and electronic thermal conductance, are determined through the Landauer approach. The underlying quasiperiodic potential belongs to the Aubry-André-Harper (AAH) family and exhibits a weakly varying spatial profile, leading to transmission characteristics that are favorable for thermoelectric optimization. The influence of phonon thermal conductance on the overall energy-conversion efficiency is also analyzed in detail. For the sake of completeness, we also critically inspect the effect of conductor to electrode coupling and the coupling asymmetry on $ZT$. We also check the thermoelectric response of conventional AAH system and an elaborate comparison is made with our chosen quantum system. Our findings highlight the potential of correlated quasiperiodic nanostructures as promising candidates for efficient thermoelectric applications.

cond-mat.mes-hall↗

Designing all possible logic gates in phononic lattices: A theoretical study

We propose a scheme for realizing thermal logic gates at the nanoscale using a phononic ring system. Two atomic sites, placed in close proximity to the ring, serve as the inputs for two-input logic operations, while a single proximity site is employed for single-input logic functionality. The logic output is encoded in the phonon transmission probability, which is calculated within the framework of non-equilibrium Green's function formalism. By appropriately tuning the ring-electrode junction configuration, all seven standard logic gates, comprising three fundamental and four combinatorial operations, are successfully realized in different phonon frequency regimes. Our results suggest that the proposed logic operations remain valid over a broad range of phonon frequencies, highlighting the generality and reliability of the proposed approach.

cond-mat.mes-hall↗