Exploring Quantum Materials at SUNY New Paltz.
Kim Reyes, Greis J. PhD
Assistant Professor of Physics
kimreyesg@newpaltz.edu
Research
I focus on understanding and engineering semiconductor materials, with an emphasis on intermediate band semiconductors. My work investigates how their electronic structure and defect physics shape key properties, and how those insights can enable device-relevant applications. In parallel, I study defects in solids and explore magnetic materials, linking atomic-scale imperfections to measurable electronic and magnetic behavior.
Undergraduate Research in Physics - Fall 2025
Calibrating Tight Binding for Biaxially Strained Graphene
Jillian Iqbal
Department of Physics and Astronomy, SUNY New Paltz
We study the effect of uniform biaxial strain on monolayer graphene using a minimal tight binding model with nearest and next-nearest neighbor hopping. A constant-hopping parametrization fails to match experimental trends, so we introduce a distance-dependent hopping of exponential form, which improves the strain dependence of low-energy observables over a realistic strain range.
Heatmaps of NNN-Driven Asymmetry in Graphene
Flavio Loja
Department of Chemistry, SUNY New Paltz
We study electron–hole asymmetry in monolayer graphene using a minimal tight-binding model that extends nearest-neighbor hopping with a next-nearest-neighbor term. Nearest-neighbor hopping alone gives particle–hole symmetry and a Dirac crossing at charge neutrality, while the next-nearest-neighbor term keeps the crossing gapless but shifts the neutrality point and skews the band curvatures across the Brillouin zone. We demonstrate this using (i) band overlays along Γ–K–M–Γ, showing a rigid energy shift and loss of mirror symmetry, and (ii) an “asymmetry map” defined by Ec(k)+Ev(k), which reveals a six-fold pattern set by the lattice geometry.
Particle–Hole Asymmetry and Barrier Uniformity in h-BN explained by NNN Tight-Binding
Michael Buccino, Kendra Scheele
Department of Physics and Astronomy, SUNY New Paltz
Hexagonal boron nitride (h-BN) is atomically flat, chemically inert, and has a wide band gap (about 6 electron volts), which suppresses interface traps and yields low, reproducible leakage even at nanometer thickness. We connect these device-level advantages to a compact tight-binding description of the 𝜋 bands using nearest-neighbor hopping plus a single next-nearest-neighbor term. This minimal model captures particle–hole asymmetry and realistic band curvature away from 𝐾. Using the evanescent solutions of the two-band dispersion in a tunneling picture, we explain why monolayer h-BN provides stable, low-leakage insulation in 2D heterostructures.