First-Principles Insights Into Electronic And Magnetic Structure At Hybrid Interfaces And Low-Dimensional Materials And Reaction On Surfaces

Author

• Bushra Ashraf, University Central of FloridaFollow

ORCID

0000-0002-1591-1187

Keywords

First-Priciples, Hybrid Interfaces, Low-Dimensional, Reactions, Surfaces

Abstract

Low-dimensional materials and transition metal surfaces/interfaces provide complementary platforms for understanding how dimensionality, symmetry, spin–orbit coupling (SOC), and interfacial charge transfer/hybridization jointly control electronic structure, emergent magnetism, and surface reactivity. Using first-principles modeling with experimental comparisons, this work aims to establish interfacial structure–property relationships across low-dimensional systems.

Strained Pd adlayers on 2H-MoS₂(0001) provide a controlled platform to separate strain-driven exchange from interface-induced quenching in an itinerant d-electron metal. Although expansive strain promotes magnetism in free-standing Pd, strong Pd–MoS₂ hybridization and charge transfer suppress the monolayer moment and leave a narrow thickness window where magnetism re-emerges in the bilayer. Spin–orbit coupling further reshapes the ground state by driving thickness-dependent magnetic anisotropy and reorientation, showing that the combined effects of strain, symmetry breaking, and interfacial coupling set magnetism. In an analogous interface-chemistry context, molecular interaction with Pt(111) demonstrates how charge redistribution and local bonding control molecular reactivity: N-methylaniline (NMA) switches from low-coverage activation to high-coverage stabilization, and under hydrocarbon coadsorption, ethylidyne acts as an active partner that enables methyl transfer to form N, N-dimethylaniline while stabilizing key intermediates.

In the quasi-one-dimensional transition-metal trichalcogenides HfSe₃, DFT calculations show maintenance of an indirect band gap as thickness increases from monolayer to bulk and reveal SOC-driven valence-band splitting near the Brillouin-zone center. Direction-resolved dispersions quantify pronounced transport anisotropy: carriers are light(∼0.27 ��_��) along the chain direction (in the direction of Hf-atoms) and significantly heavier(∼1.17 ��_��) perpendicular to the chains, consistent with polarization-dependent nano-ARPES results. Orbital- and symmetry-resolved analysis further shows that the lowest-energy optical transition is symmetry-suppressed, while the optically allowed onset arises from higher-lying states, explaining the separation between the electronic and optical gaps.

Overall, this work shows that interfaces are active design elements and that symmetry-aware modeling provides practical levers for tuning electronic, magnetic, and chemical behavior in low-dimensional materials and transition-metal surfaces.

Completion Date

2026

Semester

Spring

Committee Chair

Talat Rahman

Degree

Doctor of Philosophy (Ph.D.)

College

College of Sciences

Department

Physics

Document Type

Dissertation/Thesis

Identifier

DP0053220

STARS Citation

Ashraf, Bushra, "First-Principles Insights Into Electronic And Magnetic Structure At Hybrid Interfaces And Low-Dimensional Materials And Reaction On Surfaces" (2026). Graduate Studies Theses and Dissertations 2026. 20.
https://stars.library.ucf.edu/gradstudies_etd_2026/20