arXiv subjects

Sridevi Krishnamurthi

Publications and source records attributed to Sridevi Krishnamurthi.

5 recordsLinked to original sources

arXiv2026

BattMo -- Battery Modelling Toolbox

This paper presents the Battery Modelling Toolbox (BattMo), a flexible finite volume continuum modelling framework in MATLAB\textsuperscript{\textregistered} (\citeproc{ref-MATLAB}{The MathWorks Inc., 2025}) for simulating the performance of electro-chemical cells. BattMo can quickly setup and solve models for a variety of battery chemistries, even considering 3D designs such as cylindrical and prismatic cells. The simulation input parameters, including the material parameters and geometric descriptions, are specified through JSON schemas. In this respect, we follow the guidelines of the Battery Interface Ontology (BattINFO) to support semantic interoperability in accordance with the FAIR principles (\citeproc{ref-fair}{Wilkinson et al., 2016}). The Doyle-Fuller-Newman (DFN) (\citeproc{ref-Doyle1993ModelingCell}{Doyle et al., 1993}) approach is used as a base model. We include fully coupled thermal simulations. It is possible to include degradation mechanisms such as SEI layer growth, and the use of composite material, such as a mixture of Silicon and graphite. The models are setup in a hierarchical way, for clarity and modularity. Each model corresponds to a computational graph, which introduces a set of variables (the nodes) and functional relationship (the edges). This design enables the flexibility for changing and designing new models. The solver in BattMo uses automatic differentiation and support adjoint computation. We can therefore compute the derivative of objective functions with respect to all parameters efficiently. Gradient-based optimization routines can be used to calibrate parameters from experimental data.

physics.comp-ph↗

arXiv2022

Evidence of Spin Frustration in Vanadium Diselenide Monolayer Magnet

Monolayer VSe2, featuring both charge density wave and magnetism phenomena, represents a unique van der Waals magnet in the family of metallic two-dimensional transition-metal dichalcogenides (2D-TMDs). Herein, by means of in-situ microscopic and spectroscopic techniques, including scanning tunneling microscopy/spectroscopy, synchrotron X-ray and angle-resolved photoemission, and X-ray absorption, direct spectroscopic signatures are established, that identify the metallic 1T-phase and vanadium 3d1 electronic configuration in monolayer VSe2 grown on graphite by molecular-beam epitaxy. Element-specific X-ray magnetic circular dichroism, complemented with magnetic susceptibility measurements, further reveals monolayer VSe2 as a frustrated magnet, with its spins exhibiting subtle correlations, albeit in the absence of a long-range magnetic order down to 2 K and up to a 7 T magnetic field. This observation is attributed to the relative stability of the ferromagnetic and antiferromagnetic ground states, arising from its atomic-scale structural features, such as rotational disorders and edges. The results of this study extend the current understanding of metallic 2D-TMDs in the search for exotic low-dimensional quantum phenomena, and stimulate further theoretical and experimental studies on van der Waals monolayer magnets.

cond-mat.mtrl-sci↗

arXiv2020

1D metallic states at 2D transition metal dichalcogenide semiconductor heterojunctions

Two-dimensional (2D) lateral heterojunctions of transition metal dichalcogenides (TMDCs) have become a reality in recent years. Semiconducting TMDC layers in their common H -structure have a nonzero in-plane electric polarization, which is a topological invariant. We show by means of first-principles calculations that lateral 2D heterojunctions between TMDCs with a different polarization generate one-dimensional (1D) metallic states at the junction, even in cases where the different materials are joined epitaxially. The metallicity does not depend upon structural details, and is explained from the change in topological invariant at the junction. Nevertheless, these 1D metals are susceptible to 1D instabilities, such as charge- and spin-density waves, making 2D TMDC heterojunctions ideal systems for studying 1D physics.

cond-mat.mtrl-sci↗

arXiv2020

One-dimensional electronic instabilities at the edges of $MoS_2$

The one-dimensional metallic states that appear at the zigzag edges of semiconducting two-dimensional transition metal di-chalcogenides (TMDCs) result from the intrinsic electric polarization in these materials, which for D$_{3h}$ symmetry is a topological invariant. These 1D states are susceptible to electronic and structural perturbations that triple the period along the edge. In this paper we study possible spin density waves (SDWs) and charge-density waves (CDWs) at the zigzag edges of {\MS}, using first-principles density functional theory calculations. Depending on the detailed structures and termination of the edges, we observe either combined SDW/CDWs or pure CDWs, along with structural distortions. In all cases the driving force is the opening of a band gap at the edge. The analysis should hold for all group VI TMDCs with the same basic structure as $MoS_2$.

cond-mat.mtrl-sci↗

arXiv2020

The Sign of Three: Spin/Charge Density Waves at the Boundaries of Transition Metal Dichalcogenides

One-dimensional grain boundaries of two-dimensional semiconducting {\MX} (M= Mo,W; X=S,Se) transition metal di-chalcogenides are typically metallic at room temperature. The metallicity has its origin in the lattice polarization, which for these lattices with $D_{3h}$ symmetry is a topological invariant, and leads to one-dimenional boundary states inside the band gap. For boundaries perpendicular to the polarization direction, these states are necessarily 1/3 occupied by electrons or holes, making them susceptible to a metal-insulator transition that triples the translation period. Using density-functional-theory calculations we demonstrate the emergence of combined one-dimensional spin density/charge density waves of that period at the boundary, opening up a small band gap of $\sim 0.1$ eV. This unique electronic structure allows for soliton excitations at the boundary that carry a fractional charge of $\pm 1/3\ e$.

cond-mat.mtrl-sci↗