arXiv subjects

Juan Gomez Quispe

Publications and source records attributed to Juan Gomez Quispe.

6 recordsLinked to original sources

arXiv2026

Chiral Epitaxy: Enantioselective Growth of Chiral Nanowires on Low-Symmetry Two-Dimensional Materials

Chiral crystals exhibit useful handedness-dependent properties, including spin selectivity and circularly polarized light sensitivity, yet controlling which enantiomer forms during synthesis remains a central challenge. Existing approaches utilize molecules in solution to template crystal growth, which restricts processing conditions and introduces organic contaminants incompatible with device fabrication. Enantioselective growth of a chiral crystal on a chiral surface via vapor-phase synthesis (chiral epitaxy) has not yet been demonstrated. Here, we show chiral epitaxy of aligned tellurium nanowires on a low-symmetry two-dimensional material, ReSe2. In situ electron microscopies suggest a mechanism where handedness is determined at nucleation by the interface energy difference between Te enantiomers and the chiral substrate surface. Chiral epitaxy provides a solvent-free, vapor-solid route to homochiral crystals compatible with semiconductor and quantum manufacturing processes.

cond-mat.mtrl-sci↗

arXiv2026

Controlling HER activity and stability of $γ$- and 6,6,12-Graphyne through engineered B-N doping: DFT and Reactive MD simulations

Graphynes offer a chemically heterogeneous $sp/sp^{2}$ carbon framework with distinct electronic regimes and site-selective reactivity. Here, Density Functional Theory and Reactive Molecular Dynamics Simulations are combined to evaluate pristine, B-doped, N-doped, and B-N co-doped $γ$-graphyne and 6,6,12-graphyne (meta/ortho/para). $γ$-graphyne is a semiconductor, while 6,6,12-graphyne exhibits an anisotropic Dirac-like semi-metallic dispersion. B/N substitution reconstructs near-$E_F$ states via dopant $π$ hybridization, and B-N pairing stabilizes defects through donor-acceptor compensation, with the ortho substitutions being the most favorable. Hydrogen adsorption remains weak on pristine lattices but becomes locally optimized upon doping, with near thermo-neutral $ΔG_{\mathrm{ads}}$ 'hot spots' predominantly on $sp$-proximate carbon sites adjacent to the dopants. Reactive MD at 300 K further reveals an activity stability trade-off: B-N ortho in $γ$-graphyne sustains controlled hydrogen uptake without catastrophic bond scission, whereas B-N meta/para degrade, and 6,6,12-graphyne is generally more susceptible to over-hydrogenation. These results identify the B-N geometry as a key design variable for graphyne-based HER catalysts, which require both a favorable $ΔG_{\mathrm{ads}}$ and finite-temperature hydrogenation stability.

cond-mat.mtrl-sci↗

arXiv2025

Controlled Growth of Bronze Telluride for Scalable Thermoelectric Energy Harvesting

With the growing demand for sustainable and decentralized energy solutions, thermoelectric energy harvesting has emerged as a promising technology for directly converting waste heat into electricity through solid state, environmentally friendly means. Among copper chalcogenides, Cu2Te is a notable p-type material due to its degenerate semiconducting nature and low thermal conductivity. In this study, we present a sustainable synthesis strategy for Sn-doped Cu2Te referred to as bronze telluride (BT) via a chemical vapor deposition (CVD) assisted tellurization process using pre-alloyed Cu Sn (bronze) powder. The resulting BT exhibited an enhanced thermoelectric figure of merit (ZT) of 1 at 500 K. To assess practical applicability, BT was integrated with n type galena (PbS) in a cascaded p n thermoelectric module, which generated 2.8 mV across a temperature gradient of 35 K, demonstrating its potential for medium- to high-temperature waste heat recovery. Furthermore, thermodynamic calculations and density functional theory (DFT) simulations provided insights into the formation mechanism of Cu2Te and the thermoelectric behaviour of BT. This work introduces an efficient, scalable, and environmentally responsible pathway for developing copper-based thermoelectric materials using industrially relevant precursors.

cond-mat.mtrl-sci↗

arXiv2025

All Photonic Isolator using Atomically Thin (2D) Bismuth Telluride (Bi2Te3)

This study demonstrates that two-dimensional (2D) Bi2Te3 exhibits strong light-matter interaction, enabling a broadband Kerr nonlinear optical response. This characteristic is advantageous for nonreciprocal light propagation in passive photonic isolators. Using Spatial Self-Phase Modulation (SSPM) spectroscopy, self-induced diffraction patterns in the far field were observed at excitation wavelengths of 650 nm, 532 nm, and 405 nm to calculate the nonlinear refractive index (n2) and the third-order nonlinear optical susceptibility (chi^(3)) of the synthesized 2D Bi2Te3. The results show that 2D Bi2Te3 possesses a significantly higher nonlinear refractive index than graphene. The laser-induced hole coherence effect is responsible for the large magnitude of the third-order nonlinear susceptibility. Surface engineering techniques were also employed to enhance the response speed of the photonic system. Complementary ab initio simulations were performed to gain further insight into the observed nonlinear behavior. Leveraging the strong Kerr nonlinearity of 2D Bi2Te3, a nonlinear photonic isolator that breaks time-reversal symmetry and enables unidirectional light propagation was demonstrated. This work establishes Bi2Te3 as a novel 2D material for nonlinear photonics, expanding its potential applications in detectors, modulators, and optical switches.

physics.optics↗

arXiv2024

TPDH-Graphene as a New Anodic Material for Lithium Ion Battery: DFT-Based Investigations

The potential of tetra-penta-deca-hexagonal graphene (TPDH-gr), a recently proposed 2D carbon allotrope as an anodic material in lithium ion batteries (LIB), was investigated through density functional theory (DFT) calculations. The results indicate that Li-atom adsorption is moderate (around 0.70 eV), allowing for easy desorption. Moreover, energy barrier, diffusion coefficient, and open circuit voltage (OCV) calculations show rapid Li atom diffusion on the TPDH-gr surface, stable intercalation of lithium atoms, and good performance during the charge and discharge cycles of the LIB. These findings, combined with the intrinsic metallic nature of TPDH-gr, indicate that this new 2D carbon allotrope is a promising candidate for use as an anodic LIB material.

cond-mat.mtrl-sci↗

arXiv2024

Exploring the Electronic and Mechanical Properties of TPDH-Nanotube: Insights from Ab initio and Classical Molecular Dynamics Simulations

Tetra-Penta-Deca-Hexa-graphene (TPDH) is a new 2D carbon allotrope with attractive electronic and mechanical properties. It is composed of tetragonal, pentagonal, and hexagonal carbon rings. When TPDH-graphene is sliced into quasi-one-dimensional (1D) structures like nanoribbons, it exhibits a range of behaviors, from semi-metallic to semiconducting. An alternative approach to achieving these desirable electronic (electronic confinement and/or non-zero electronic band gap) properties is the creation of nanotubes (TPDH-NT). In the present work, we carried out a comprehensive study of TPDH-NTs combining Density Functional Theory (DFT) and Classical Reactive Molecular Dynamics (MD). Our results show structural stability and a chiral dependence on mechanical properties. Similarly to standard carbon nanotubes, TPDH-NT can be metallic or semiconductor. MD results show Young's modulus values exceeding $700$ GPa, except for nanotubes with very small radii. However, certain chiral TPDH-NTs (n,m) display values both below and above $700$ GPa, particularly for those with small radii. The analyses of the angle and C-C bond length distributions underscore the significance of the tetragonal and pentagonal rings in determining the mechanical response of TPDH-NTs (n,0) and (0,n), respectively.

cond-mat.mtrl-sci↗