Sreetosh Goswami | Searcharxiv

arXiv2025

Molecular Mechanism Enabling Linearity and Symmetry in Neuromorphic Elements

For over a decade, linear and symmetric weight updates have remained the elusive holy grail in neuromorphic computing. Here, we unveil a kinetically controlled molecular mechanism driving a near-ideal neuromorphic element, capable of precisely modulating conductance linearly across 16,500 analog levels spanning four orders of magnitude. Our findings, supported by experimental data and mathematical modelling, demonstrate how nonlinear processes such as nucleation can be orchestrated within small perturbation regimes to achieve linearity. This establishes a groundwork for routinely realizing these long-sought neuromorphic features across a broad range of material systems.

cs.ET↗

arXiv2020

Evidence of Rotational Fröhlich Coupling in Polaronic Trions

Electrons commonly couple through Fröhlich interactions with longitudinal optical phonons to form polarons. However, trions possess a finite angular momentum and should therefore couple instead to rotational optical phonons. This creates a polaronic trion whose binding energy is determined by the crystallographic orientation of the lattice. Here, we demonstrate theoretically within the Fröhlich approach and experimentally by photoluminescence emission that the bare trion binding energy (20 meV) is significantly enhanced by the phonons at the interface between the two-dimensional semiconductor MoS$_2$ and the bulk transition metal oxide SrTiO$_3$. The low-temperature {binding energy} changes from 60 meV in [001]-oriented substrates to 90 meV for [111] orientation, as a result of the counter-intuitive interplay between the rotational axis of the MoS$_2$ trion and that of the SrTiO$_3$ phonon mode.

cond-mat.mes-hall↗