arXiv subjects

Matthew P. Sherburne

Publications and source records attributed to Matthew P. Sherburne.

3 recordsLinked to original sources

arXiv2026

Mesoscale Crystallographic Helicity in Confined Tellurium Quantum Wires

Helical order can facilitate symmetry breaking and emergent physical responses in crystalline materials, yet how intrinsic chirality manifests beyond atomic length scales remains poorly understood. Here, the direct observation and quantitative characterization of long-range crystallographic helicity in template-grown tellurium (Te) quantum wires on amorphous substrates are reported. Four-dimensional scanning transmission electron microscopy (4D-STEM) enables quantitative mapping of crystallographic orientation with nanometer-scale spatial resolution. The resulting orientation maps establish continuous mesoscale lattice twisting, providing direct evidence of long-range crystallographic helicity. Correlated orientation and strain mapping reveal pronounced lateral strain heterogeneity, with compressive strain concentrated within the wire interior. Systematic analysis across multiple wires suggests that higher twist rates are generally associated with weaker lateral compressive strain, narrower wires, and better atomic chain - template axis alignment. Complementary first-principles calculations on finite Te nanorods further suggest that twisting is intrinsically accessible in nucleus-scale Te clusters and strain can bias the preferred torsional state. Together, these results support a growth-incorporated, strain-biased picture in which nanoscale confinement and anisotropic strain facilitate torsional relaxation and stabilize mesoscale helicity in Te nanostructures highlighting strain and confinement as potential routes for engineering chiral lattice states in van der Waals nanostructures.

cond-mat.mtrl-sci↗

arXiv2023

Elucidating the Mechanism of Large Phosphate Molecule Intercalation Through Graphene Heterointerfaces

Intercalation is a process of inserting chemical species into the heterointerfaces of two-dimensional (2D) layered materials. While much research has focused on intercalating metals and small gas molecules into graphene, the intercalation of larger molecules through the basal plane of graphene remains highly unexplored. In this work, we present a new mechanism for intercalating large molecules through monolayer graphene to form confined oxide materials at the graphene-substrate heterointerface. We investigate the intercalation of phosphorus pentoxide (P2O5) molecules directly from the vapor phase and confirm the formation of confined P2O5 at the graphene heterointerface using various techniques. Density functional theory (DFT) corroborate the experimental results and reveal the intercalation mechanism, whereby P2O5 dissociates into small fragments catalyzed by defects in the graphene that then permeates through lattice defects and reacts at the heterointerface to form P2O5. This process can also be used to form new confined metal phosphates (e.g., 2D InPO4). While the focus of this study is on P2O5 intercalation, the possibility of intercalation from pre-dissociated molecules catalyzed by defects in graphene may exist for other types of molecules as well. This study is a significant milestone in advancing our understanding of intercalation routes of large molecules via the basal plane of graphene, as well as heterointerface chemical reactions leading to the formation of distinctive confined complex oxide compounds.

cond-mat.mtrl-sci↗

arXiv2020

The Bright Side and the Dark Side of Hybrid Organic Inorganic Perovskites

The previously developed bistable amphoteric native defect (BAND) model is used for a comprehensive explanation of the unique photophysical properties and for understanding the remarkable performance of perovskites as photovoltaic materials. It is shown that the amphoteric defects in donor (acceptor) configuration capture a fraction of photoexcited electrons (holes) dividing them into two groups: higher energy bright and lower energy dark electrons (holes). The spatial separation of the dark electrons and the dark holes and the k-space separation of the bright and the dark charge carriers reduce electron hole recombination rates, emulating the properties of an ideal photovoltaic material with a balanced, spatially separated transport of electrons and holes. The BAND model also offers a straightforward explanation for the exceptional insensitivity of the photovoltaic performance of polycrystalline perovskite films to structural and optical inhomogeneities. The blue-shifted radiative recombination of bright electrons and holes results in a large anti-Stokes effect that provides a quantitative explanation for the spectral dependence of the laser cooling effect measured in perovskite platelets.

physics.app-ph↗