Deriving New Two-Dimensional (2D) Layered Materials Using First-Principles Combined with Thermodynamics and Periodic Trends

Abstract

The emergence of two-dimensional (2D) layered materials has reshaped the design space for next-generation electronics, energy devices, and low-dimensional quantum systems. While exfoliation of known layered compounds has expanded this library, predictive strategies for discovering entirely new 2D systems remain limited. This dissertation presents a methodology for 2D materials discovery rooted in firstprinciples density functional theory (DFT), thermodynamic analysis, and periodic trends of basic chemical descriptors. At the core of this approach is the integration of electronic structure analysis with additional considerations to guide experimental efforts. The first half of this dissertation discusses how the addition of thermodynamic modeling methods to first-principles can approximate surface reactivity at the solid– liquid interface. This includes both pedagogical and technical contributions to the interpretation of band structure and bonding behavior through projected density of states (PDOS), and the adaptation of the DFT + Solvent Ion Model (DSIM) to study surface transformations under aqueous conditions. These methods are applied to examine how surface chemistry governs exfoliation stability in ABX-type 2D layered materials. A quantitative workflow is developed for evaluating surface exchange reactions and stability under redox-active conditions in layered pnictides, enabling predictions of 2D monolayer formation pathways that are determined using both electronic and thermodynamic descriptors. The second half of this dissertation details the compositional tuning of bulk 2D van der Waals ferroelectrics such as CuInP₂X₆ (X = S, Se), where DFT is used to examine how isovalent substitution at the P and In sites modifies polarization and band gap through bonding asymmetry and lattice flexibility. Cation ordering, host lattice stiffness, and ionic radii/electronegativity mismatches are evaluated to derive design rules linking structural distortion to functional response. Finally, a data-guided study combines structural mining of the Inorganic Crystal Structure Database with quantum structural diagram analysis to identify 83 new quaternary phosphochalcogenides as promising 2D candidates. These compounds are mapped by symmetry type and atomic coordination, allowing the construction of Villars-style design maps to highlight trends in stability and dimensional reduction. These efforts establish a transferable computational strategy for predicting 2D materials beyond known structure types. The findings offer guidance for experimental synthesis, enable structural prediction strategies linked to chemical and electronic descriptors, and contribute to a broader translation of solid-state physics concepts into chemically driven materials discovery.