Unified Entropy-Ruled Einstein Relation for Bulk and Low-Dimensional Systems: A Hopping to Band Shift Analysis

In this letter, we present the unified paradigm on entropy-ruled Einstein diffusion-mobility relation ({\mu}/D ratio) for all dimensional systems (1D, 2D and 3D) of molecules and materials. The different dimension-associated fractional value of the variation in differential entropy with respect to the chemical potential ({\Delta}h/{\Delta}{\eta}) gives the quantum-classical transition version of {\mu}/D relation. This is a new alternative version for quantum devices, instead of Einstein original relation of {\mu}/D = q/kT; where q, k and T are the electric charge, Boltzmann constant and temperature, respectively. It is found that the fractional value of {\Delta}h/{\Delta}{\eta} for {\mu}/D ratio for different dimensional systems or devices is a direct consequences with the average energy-Fermi energy relation, which can varies with the typical dimensions, whether the system belongs to 1D or 2D or 3D. This unified entropy-ruled transport formalism works well for both the quantum and classical systems with equilibrium as well as non-equilibrium conditions. Based on the dimensional dependent entropy-ruled {\mu}/D factor, the Navamani-Shockley diode equation is transformed.

K. Navamani · 2023