Bio

Dr. Evangelista's primary research focus lies in computational modeling and theoretical analysis of semiconductor materials using advanced quantum mechanical methods, including Density Functional Theory, Quantum Monte Carlo, and ab-initio Molecular Dynamics. Evangelista investigates the electronic, structural, and mechanical properties of materials, collaborating closely with experimental groups to bridge theoretical predictions with empirical results. He is also interested in the development of empirical potentials and enhancing materials modeling through the application of machine learning techniques.

Evangelista entered the Department of Materials Science and Engineering at the University of Delaware as a Ph.D. candidate in 2018, after completing an master degree in Physics 2016-2018 at Federal Fluminense University (Brazil). Recent work includes collaborations with experimental groups to bridge theoretical predictions with empirical results, as well as applying machine learning to creating of empirical potentials to accelerate materials modeling. Evangelista has also contributed to understanding electron mobility in metal-oxide semiconductors and strain effects in two-dimensional materials. These studies showcase his expertise in electronic structure and materials design for next-generation semiconductor technologies.

Stanford Advisors

Contact

  • Academic
    igord@stanford.edu
    University - Scholar Department: SLAC National Accelerator Laboratory Position: Postdoctoral Scholar

Additional Info

Links

All Publications

  • Large Rashba spin splittings in bulk and monolayer of BiAs PHYSICAL REVIEW MATERIALS Zubair, M., Evangelista, I., Khalid, S., Medasani, B., Janotti, A. 2024; 8 (5)

    View details for DOI 10.1103/PhysRevMaterials.8.054604

    View details for Web of Science ID 001231846100006

  • Doping the Undopable: Hybrid Molecular Beam Epitaxy Growth, n-Type Doping, and Field-Effect Transistor Using CaSnO<sub>3</sub> ACS NANO Liu, F., Golani, P., Truttmann, T. K., Evangelista, I., Smeaton, M. A., Bugallo, D., Wen, J., Manjeshwar, A., May, S. J., Kourkoutis, L. F., Janotti, A., Koester, S. J., Jalan, B. 2023; 17 (17): 16912-16922

    Abstract

    The alkaline earth stannates are touted for their wide band gaps and the highest room-temperature electron mobilities among all of the perovskite oxides. CaSnO3 has the highest measured band gap in this family and is thus a particularly promising ultrawide band gap semiconductor. However, discouraging results from previous theoretical studies and failed doping attempts had described this material as "undopable". Here we redeem CaSnO3 using hybrid molecular beam epitaxy, which provides an adsorption-controlled growth for the phase-pure, epitaxial, and stoichiometric CaSnO3 films. By introducing lanthanum (La) as an n-type dopant, we demonstrate the robust and predictable doping of CaSnO3 with free electron concentrations, n3D, from 3.3 × 1019 cm-3 to 1.6 × 1020 cm-3. The films exhibit a maximum room-temperature mobility of 42 cm2 V-1 s-1 at n3D = 3.3 × 1019 cm-3. Despite having a comparable radius as the host ion, La expands the lattice parameter. Using density functional calculations, this effect is attributed to the energy gain by lowering the conduction band upon volume expansion. Finally, we exploit robust doping by fabricating CaSnO3-based field-effect transistors. The transistors show promise for CaSnO3's high-voltage capabilities by exhibiting low off-state leakage below 2 × 10-5 mA/mm at a drain-source voltage of 100 V and on-off ratios exceeding 106. This work serves as a starting point for future studies on the semiconducting properties of CaSnO3 and many devices that could benefit from CaSnO3's exceptionally wide band gap.

    View details for DOI 10.1021/acsnano.3c04003

    View details for Web of Science ID 001063855400001

    View details for PubMedID 37638732

  • Structural Phase Transitions between Layered Indium Selenide for Integrated Photonic Memory ADVANCED MATERIALS Li, T., Wang, Y., Li, W., Mao, D., Benmore, C. J., Evangelista, I., Xing, H., Li, Q., Wang, F., Sivaraman, G., Janotti, A., Law, S., Gu, T. 2022; 34 (26): e2108261

    Abstract

    The primary mechanism of optical memoristive devices relies on phase transitions between amorphous and crystalline states. The slow or energy-hungry amorphous-crystalline transitions in optical phase-change materials are detrimental to the scalability and performance of devices. Leveraging an integrated photonic platform, nonvolatile and reversible switching between two layered structures of indium selenide (In2 Se3 ) triggered by a single nanosecond pulse is demonstrated. The high-resolution pair distribution function reveals the detailed atomistic transition pathways between the layered structures. With interlayer "shear glide" and isosymmetric phase transition, switching between the α- and β-structural states contains low re-configurational entropy, allowing reversible switching between layered structures. Broadband refractive index contrast, optical transparency, and volumetric effect in the crystalline-crystalline phase transition are experimentally characterized in molecular-beam-epitaxy-grown thin films and compared to ab initio calculations. The nonlinear resonator transmission spectra measure of incremental linear loss rate of 3.3 GHz, introduced by a 1.5 µm-long In2 Se3 -covered layer, resulted from the combinations of material absorption and scattering.

    View details for DOI 10.1002/adma.202108261

    View details for Web of Science ID 000799491400001

    View details for PubMedID 35435286

https://orcid.org/0000-0003-2402-9484