arXiv subjects

Vineet Pandey

Publications and source records attributed to Vineet Pandey.

5 recordsLinked to original sources

arXiv2026

Impact of Disorder Dynamics and Multi-Domain Kinetics on the Sliding Ferroelectricity of CVD-Grown 3R-WSe2 Bilayers

Sliding ferroelectricity in van der Waals (vdW) layered systems has emerged as a promising route toward non-volatile nanoscale devices, where interlayer displacement in non-centrosymmetric bilayers generates an out-of-plane polarization. In particular, 3R-stacked bilayer transition metal dichalcogenides (TMDs) grown via chemical vapor deposition (CVD) have been shown to host such polarization due to broken inversion symmetry. However, a detailed investigation of the 2D ferroelectric (FE) properties of CVD-grown 2D films, particularly the role of intrinsic disorder, such as structural defects and domain structure, remains poorly understood. Here, we investigate the FE switching characteristics of CVD-grown 3R-stacked WSe2 using a graphene-based ferroelectric field-effect transistor (graphene-FE-FET) architecture, where graphene serves as a highly sensitive probe of induced charge modulation due to polarization switching of FEs. We show that the growth-induced structural disorder significantly impacts polarization switching, while multi-domain kinetics governs the evolution of the FE response. These findings provide important insights into the design and optimization of FE devices based on vdW materials.

cond-mat.mtrl-sci↗

arXiv2025

Skyrmionic Transport and First Order Phase Transitions in Twisted Bilayer Graphene Quantum Hall Ferromagnet

Large-angle twisted bilayer graphene (TBLG) realizes a multicomponent quantum Hall (QH) platform of spin, valley and layer pseudospins with strong Coulomb interaction-driven symmetry broken phases. Here, we investigate the low energy Landau-level spectrum of layer-decoupled TBLG and identify skyrmion-textured charged excitations and a field-induced insulating transition to an intervalley coherent state at zero-filling factor. Symmetric potential difference perpendicular to TBLG demonstrated layer coherent population of ground states with uniform energy barriers, while the charge imbalance in the layers at finite displacement field led to multidomain nucleation and a pronounced hysteresis in the exchange-dominated transport regime suggesting first order phase transitions between different QH ferromagnetic ground states.

cond-mat.mes-hall↗

arXiv2023

Probing interlayer interactions and commensurate-incommensurate transition in twisted bilayer graphene through Raman spectroscopy

Twisted 2D layered materials have garnered a lot of attention recently as a class of 2D materials whose interlayer interactions and electronic properties are dictated by the relative rotation / twist angle between the adjacent layers. In this work, we explore a prototype of such a twisted 2D system, artificially stacked twisted bilayer graphene (TBLG), where we probe the changes in the interlayer interactions and electron-phonon scattering pathways as the twist angle is varied from 0° to 30°, using Raman spectroscopy. The long range Moiré potential of the superlattice gives rise to additional intravalley and intervalley scattering of the electrons in TBLG which have been investigated through their Raman signatures. The density functional theory (DFT) calculations of the electronic band structure of the TBLG superlattices was found to be in agreement with the resonant Raman excitations across the van Hove singularities in the valence and conduction bands predicted for TBLG due to hybridization of bands from the two layers. We also observe that the relative rotation between the graphene layers has a marked influence on the second order overtone and combination Raman modes signalling a commensurate-incommensurate transition in TBLG as the twist angle increases. This serves as a convenient and rapid characterization tool to determine the degree of commensurability in TBLG systems.

cond-mat.mtrl-sci↗

arXiv2016

Integrating citizen science with online learning to ask better questions

Online learners spend millions of hours per year testing their new skills on assignments with known answers. This paper explores whether framing research questions as assignments with unknown answers helps learners generate novel, useful, and difficult-to-find knowledge while increasing their motivation by contributing to a larger goal. Collaborating with the American Gut Project, the world's largest crowdfunded citizen science project, we deploy Gut Instinct to allow novices to generate hypotheses about the constitution of the human gut microbiome. The tool enables online learners to explore learning material about the microbiome and create their own theories around causal variances for microbiome. Building on crowdsourcing or serious games that use people as replaceable units, this work-in-progress lays our plans for how people (a) use their personal knowledge (b) towards solving a larger real-world goal (c) that can provide potential benefits to them. We hope to demonstrate that Gut Instinct citizen scientists generate useful hypotheses, perform better on learning tasks than traditional MOOC learners, and are better engaged with the learning material.

cs.HC↗

arXiv2016

An HCI View of Configuration Problems

In recent years, configuration problems have drawn tremendous attention because of their increasing prevalence and their big impact on system availability. We believe that many of these problems are attributable to today's configuration interfaces that have not evolved to accommodate the enormous shift of the system administrator group. Plain text files, as the de facto configuration interfaces, assume administrators' understanding of the system under configuration. They ask administrators to directly edit the corresponding entries with little guidance or assistance. However, this assumption no longer holds for todays administrator group which has expanded greatly to include non- and semi-professional administrators. In this paper, we provide an HCI view of today's configuration problems, and articulate system configuration as a new HCI problem. Moreover, we present the top obstacles to correctly and efficiently configuring software systems, and most importantly their implications on the design and implementation of new-generation configuration interfaces.

cs.HC↗