Professor Fouad El Haj Hassan received the Ph.D. degree in 2000 in condensed matter Physics, from Metz University, France. He joined Lebanese University-Faculty of sciences (I) in 2001, where he is currently a Professor of Physics and condensed matter. Prof. El Haj Hassan is the director of Platform for research and analysis in Environmental Sciences (PRASE – EDST - UL) since October 2015. Coordinator of the Faculty of sciences 4 - annex Baalbek between 2009 and 2013.
Prof. El Haj Hassan is a holder of a Lebanese Research Chair in computational Physics; he is founder and TPC of several international conferences such as the MEDGREEN-LB 2011, ICM2013 IEEE, ICM2015 IEE and ICM2021 IEE. He is plenary speaker in many international conferences and editor board of "Condensed matter physics" and "the scientific world journal". He is referee for more than 12 international journals. Prof El Haj Hassan published 117 peer reviewed journal papers with about 1917 citations and one book chapter. He
Optothermal Raman analysis of thermal conductance and boundary resistance in a subwavelength single nanoparticle Nourhan Barakat, Fouad El Haj Hassan, Michel Kazan Journal of Applied Physics, 2025 We present optothermal Raman spectroscopy as a powerful technique for characterizing the thermal properties of individual subwavelength nanoparticles. This method enables the extraction of the intrinsic thermal conductance of an individual nanoparticle with an average size representative of the inclusion population and the thermal resistance at the interface between the nanoparticle and its surrounding matrix. By overcoming the spatial resolution limitations of conventional techniques, such as scanning thermal microscopy, and eliminating the need for complex nanoscale heat transfer modeling, optothermal Raman spectroscopy provides direct, size-independent measurements with high accuracy. The technique involves measuring the thermal conductance of target nanoparticles embedded in a matrix of smaller, low-density particles at varying mass fractions. These measurements are then fitted to the effective medium theory to extract both the intrinsic thermal conductance and boundary thermal resistance of the nanoparticles. Validation studies were conducted on monoclinic gallium oxide (β-Ga₂O₃, 590 nm) and zinc oxide (ZnO, 500 nm) particles in a granular silicon matrix, as well as silicon (Si, 100 nm) nanoparticles in a granular carbon matrix. The β-Ga₂O₃ and ZnO particles, with bulk-like thermal properties, served as benchmarks, while the Si nanoparticles exhibited size-dependent thermal behavior. Measurements relied on the resonance frequency of Si as a precise thermometric signal, and results were corroborated by first-principles calculations. By providing direct, reliable measurements without intricate modeling, optothermal Raman spectroscopy offers significant advantages for thermal property characterization. This versatile technique holds great promise for advancing research in materials science and nanotechnology.
Ultralow thermal conductivity in Si-Ge nanograin mixtures: A cost-effective granular material for thermoelectric applications Nourhan Barakat, A. Akkoush, Fouad El Haj Hassan, Michel Kazan Journal of Applied Physics, 2024 This paper presents a theoretical study of the thermal conductivity of Si–Ge nanograin mixtures using a multiscale computational methodology based on solving the Boltzmann transport equation for phonons with first-principles techniques. A size-dependent correction factor is developed to account for the spatial dependence of the phonon distribution function on nanograin size, with parameters derived from the phonon properties of infinite Si and Ge crystals. This approach makes it possible to accurately calculate the thermal conductivity within a single nanograin, using force constants obtained from first-principles calculations. Thermal energy transport by phonons across grain boundaries is modeled by accounting for phonon transmission by two-phonon processes, weighting specular, and diffuse transmission for each phonon mode as a function of the root-mean-square roughness of the boundary relative to the phonon wavelength. The boundary thermal conductance model, previously validated against experimental data, is implemented using first-principles techniques. This approach excludes specular transmission for phonon modes with specific symmetries while ensuring conservation of the total number of modes in each symmetry class. The study examines the influence of grain size, nanograin mixture composition, temperature, and boundary asperities on the thermal conductivity of nanograin mixtures.
Modification of the Acoustic Mismatch Model and Diffuse Mismatch Model for Accurate Prediction of Interface Thermal Conductance at Low Temperatures Nourhan Barakat, Fouad El Haj Hassan, Michel Kazan ASME Journal of Heat and Mass Transfer, 2024 Houston's method for summing phonon modes in the Brillouin zone is applied to exclude specular transmission of phonon modes of specific symmetries, thus, modifying the Acoustic Mismatch Model when phonon heat flux is incident from a heavier to a lighter medium. The Houston method is also used to impose conservation of the number of phonons in each direction of high-symmetry, thus modifying the detailed balance theorem and the Diffuse Mismatch Model. Based on the assumption that phonons are in equilibrium at the interface and are transmitted specularly or diffusely by two-phonon elastic processes, interpolation between the modified Acoustic Mismatch Model and the modified Diffuse Mismatch Model has led to a general analytical formalism for low-temperature interface thermal conductance. The Debye temperature, the only parameter in the derived formalism, is expressed as a function of temperature by assimilating numerically obtained specific heat values to the Debye expression for specific heat. Previous measurements of the low-temperature thermal conductance of smooth and rough interfaces between dissimilar materials could be reproduced numerically without adjustment of model parameters, demonstrating the importance of modifications to the Acoustic Mismatch Model and the Diffuse Mismatch Model and supporting the hypothesis that anharmonic processes play a minimal role in heat transport across the interfaces studied below room temperature. The formalism developed is used to study the thermal conductance of the interface between silicon and germanium because of the potential of silicon-germanium nanocomposites for thermoelectric applications.
Electrical conductivity and impedance calculated beyond τ-approximation Farraj Maallawi, Fouad El Haj Hassan Indian Journal of Physics, 2021 In the present work, we include the electrons that penetrate the skin layer by seeing their effects on electrical conductivity and metal impedance in both cases of normal and anomalous skin effects. The τ-approximation is used in order to derive new formulas for the electrical conductivity and surface impedance of the normal metal based on the new form of Boltzmann’s kinetic equation.
Modulating phonon-electron Fano resonance in Si nanoparticles through laser exposure and properties of surrounding nanoparticles N Barakat, FEH Hassan, M Kazan Journal of Physics and Chemistry of Solids 202, 112700 , 2025 2025 Citations: 2
Theoretical investigation of the thermal conductivity of Ga2O3 polymorphs F Safieddine, FEH Hassan, M Kazan Solid State Communications 394, 115715 , 2024 2024 Citations: 7
Thermal properties of In2O3 and α-Ga2S3 compounds F Safieddine, FEH Hassan, M Kazan Solid State Communications 391, 115629 , 2024 2024 Citations: 2
Modification of the Acoustic Mismatch Model and Diffuse Mismatch Model for Accurate Prediction of Interface Thermal Conductance at Low Temperatures N Barakat, FEH Hassan, M Kazan ASME Journal of Heat and Mass Transfer 146 (4), 041401 , 2024 2024 Citations: 4
Comparative study of the fundamental properties of Ga2O3 polymorphs F Safieddine, FEH Hassan, M Kazan Journal of Solid State Chemistry 312, 123272 , 2022 2022 Citations: 27
Ab-initio study of the electronic structure of LaF including spin–orbit coupling J Assaf, R Assaf, FEH Hassan Journal of Molecular Modeling 28 (6), 170 , 2022 2022 Citations: 2
Electrical conductivity and impedance calculated beyond τ -approximation: F Maallawi and F El Haj Hassan F Maallawi, F El Haj Hassan Indian Journal of Physics 95 (3), 433-437 , 2021 2021
Tuning the hybrid borophene−/graphene-ionic liquid interface: Effect of metal cations on the electronic and photonic properties K Zhour, JM Otero-Mato, FEH Hassan, H Fahs, M Vaezzadeh, ... Journal of Molecular Liquids 321, 114759 , 2021 2021 Citations: 13
Water-silanol interactions on the amorphous silica surface: A dispersion-corrected DFT investigation Y Berro, M Badawi, FEH Hassan, M Kassir, F Tielens Journal of Molecular Liquids 320, 114496 , 2020 2020 Citations: 22
Ab-initio study of ordered III–V antimony-based semiconductor alloys F Annane, H Meradji, S Ghemid, H Bendjeddou, FEH Hassan, ... Pramana 94 (1), 107 , 2020 2020 Citations: 13
Electronic and optical properties of borophene and graphene with an adsorbed ionic liquid: A density functional theory study K Zhour, JM Otero-Mato, FEH Hassan, H Fahs, M Vaezzadeh, ... Journal of Molecular Liquids 316, 113803 , 2020 2020 Citations: 18
Imprinting isolated single iron atoms onto mesoporous silica by templating with metallosurfactants Y Berro, S Gueddida, Y Bouizi, C Bellouard, EE Bendeif, A Gansmuller, ... Journal of colloid and interface science 573, 193-203 , 2020 2020 Citations: 34
Skyrmion based random bit generator I Medlej, A Hamadeh, FEH Hassan Physica B: Condensed Matter 579, 411900 , 2020 2020 Citations: 22
Ab-initio study of ordered III–V antimony-based semiconductor alloys GaP1− xSbx and AlP1− xSbx F Annane, H Meradji, S Ghemid, H Bendjeddou, F El Haj Hassan, ... 2020
First-principles investigation of the structural, elastic, electronic, and optical properties of semiconducting AgBr 1– x I x (0 ≤ x ≤ 1) ternary alloys in rock-salt and … H Rekab-Djabri, M Drief, MM Abdus Salam, S Daoud, F El Haj Hassan, ... Canadian Journal of Physics 98 (9), 834-848 , 2020 2020 Citations: 17
First-principles calculations to investigate half-metallic ferromagnetism in Zn 0.50 Ti 0.50 S alloy by using DFT + U calculations A Bahnes, MEA Monir, Y Mouchaal, FEH Hassan, Z Bahnes, AB Reguig Philosophical Magazine 99 (23), 3000-3014 , 2019 2019 Citations: 3
Ab initio study of the adsorption of Potassium on B, N, and BN-doped graphene heterostructure K Zhour, FEH Hassan, H Fahs, M Vaezzadeh Materials Today Communications 21, 100676 , 2019 2019 Citations: 13
Atomistic description of phenol, CO and H2O adsorption over crystalline and amorphous silica surfaces for hydrodeoxygenation applications Y Berro, S Gueddida, S Lebègue, A Pasc, N Canilho, M Kassir, ... Applied Surface Science 494, 721-730 , 2019 2019 Citations: 47
Fundamental properties of scandium chalcogenides and their alloys: DFT study: AA Ahmad et al. AA Ahmad, S Mahmoud, B Alshafaay, R Halabi, F El Haj Hassan Indian Journal of Physics 93 (9), 1129-1135 , 2019 2019 Citations: 4
ab-initio investigations of electronic and magnetic properties of the tetragonal chalcopyrite BeTiTe 2 compound: DFT + U study MEA Monir, FEH Hassan, A Bahnes, H Baltach, AB Reguig Philosophical Magazine 99 (17), 2185-2197 , 2019 2019
MOST CITED SCHOLAR PUBLICATIONS
Full potential linearized augmented plane wave calculations of structural and electronic properties of BN, BP, BAs and BSb A Zaoui, FEH Hassan Journal of Physics: Condensed Matter 13 (2), 253-262 , 2001 2001 Citations: 237
High pressure study of structural and electronic properties of calcium chalcogenides Z Charifi, H Baaziz, F El Haj Hassan, N Bouarissa Journal of Physics: Condensed Matter 17 (26), 4083-4092 , 2005 2005 Citations: 188
First-principles investigation of BNxP1− x, BNxAs1− x and BPxAs1− x ternary alloys FEH Hassan, H Akbarzadeh Materials Science and Engineering: B 121 (1-2), 170-177 , 2005 2005 Citations: 145
Theoretical study of structural, electronic, and thermal properties of CdS, CdSe and CdTe compounds S Ouendadji, S Ghemid, H Meradji, FEH Hassan Computational Materials Science 50 (4), 1460-1466 , 2011 2011 Citations: 123
Ground state properties and structural phase transition of beryllium chalcogenides FEH Hassan, H Akbarzadeh Computational materials science 35 (4), 423-431 , 2006 2006 Citations: 92
Structural, electronic and thermodynamic properties of wide band gap MgxZn1− xO alloy B Amrani, R Ahmed, FEH Hassan Computational Materials Science 40 (1), 66-72 , 2007 2007 Citations: 80
Structural and electronic properties of the wide-gap Zn 1− x Mg x S, Zn 1− x Mg x Se and Zn 1− x Mg x Te ternary alloys Z Charifi, F El Haj Hassan, H Baaziz, S Khosravizadeh, SJ Hashemifar, ... Journal of Physics: Condensed Matter 17 (44), 7077-7088 , 2005 2005 Citations: 78
Structural and electronic properties of matlockite MFX (MSr, Ba, Pb; XCl, Br, I) compounds F El haj Hassan, H Akbarzadeh, SJ Hashemifar, A Mokhtari Journal of Physics and Chemistry of Solids 65 (11), 1871-1878 , 2004 2004 Citations: 78
Structural properties of copper halides FEH Hassan, A Zaoui, W Sekkal Materials Science and Engineering: B 87 (1), 40-47 , 2001 2001 Citations: 76
FP‐LAPW investigations of Zn 1– x Be x S, Zn 1– x Be x Se and Zn 1– x Be x Te ternary alloys H Baaziz, Z Charifi, F El Haj Hassan, SJ Hashemifar, H Akbarzadeh physica status solidi (b) 243 (6), 1296-1305 , 2006 2006 Citations: 73
First‐principles calculations on the origins of the gap bowing in BeS x Se 1– x , BeS x Te 1– x and BeSe x Te 1– x alloys F El Haj Hassan Physica status solidi (b) 242 (4), 909-915 , 2005 2005 Citations: 71
First-principles elastic and bonding properties of barium chalcogenides FEH Hassan, H Akbarzadeh Computational materials science 38 (2), 362-368 , 2006 2006 Citations: 70
First principle calculations of structural, electronic, thermodynamic and optical properties of Pb 1− x Ca x S,Pb 1− x Ca x Se and Pb 1− x Ca x Te ternary alloys C Sifi, H Meradji, M Slimani, S Labidi, S Ghemid, EB Hanneche, ... Journal of Physics: Condensed Matter 21 (19), 195401 , 2009 2009 Citations: 69
Structural properties of boron compounds at high pressure FEH Hassan, H Akbarzadeh, M Zoaeter Journal of Physics: Condensed Matter 16 (3), 293-301 , 2004 2004 Citations: 69
First-principles study of the ternary semiconductor alloys (Ga, Al)(As, Sb) FEH Hassan, A Breidi, S Ghemid, B Amrani, H Meradji, O Pagès Journal of Alloys and Compounds 499 (1), 80-89 , 2010 2010 Citations: 68
Comparative study of structural and electronic properties of GaSe and InSe polytypes J Srour, M Badawi, F El Haj Hassan, A Postnikov The Journal of chemical physics 149 (5) , 2018 2018 Citations: 66
First principle investigation of AlAs and AlP compounds and ordered AlAs1− xPx alloys F Annane, H Meradji, S Ghemid, FEH Hassan Computational Materials Science 50 (2), 274-278 , 2010 2010 Citations: 65
Computational study of AgCl and AgBr semiconductors T Benmessabih, B Amrani, FEH Hassan, F Hamdache, M Zoaeter Physica B: Condensed Matter 392 (1-2), 309-317 , 2007 2007 Citations: 60
Density functional study of quaternary semiconductor alloys F El Haj Hassan, SJ Hashemifar, H Akbarzadeh Physical Review B—Condensed Matter and Materials Physics 73 (19), 195202 , 2006 2006 Citations: 57
Theoretical calculations of the high-pressure phases of SnO2 FEH Hassan, S Moussawi, W Noun, C Salameh, AV Postnikov Computational materials science 72, 86-92 , 2013 2013 Citations: 56
