1. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
Activity of our research group
“Condensed matter and theoretical physics”
Laboratoire de Physique et d’électronique (LPE)
7 researchers
4 PhD students (2010) PhD students (2015)
35 papers in an international journals ( )
4 chapter in a book (2014)
20 conferences ( )
Foundation of the M2R “fundamental physics” (2009)
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

2. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
First-principles investigation within the improved modified
Becke–Johnson potential of CuInSe2 and CuGaSe2
Fouad EL HAJ HASSAN
Université Libanaise, Faculté des sciences (I), Laboratoire de Physique et d’électronique (LPE), Elhadath, Beyrouth, Liban
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

3. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
Outline
Introduction
Method of calculations
Density functional theory (DFT)
Full potential-linearized augmented plan wave
method (FP-LAPW)
Results
Structural and electronic properties
Thermal properties
Conclusions
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

4. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
Introduction
Copper based chalcopyrite CuGaSe2 with its:
Tetragonal structure
High band gap
High efficiency
Widely used in
Solar cells
Light emitting diodes
Nonlinear optics
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

5. Method of calculations
Approximation
M. Born
R. Oppenheimer
Born-Oppenheimer
1st International Conference on Numerical Physics, Oran, October 13-15, 2012

6. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
Hartree-Fock Theory
D. Hartree
V. Fock
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

7. Density functional theory DFT
Kohn was awarded the Nobel prize in 1998
P. Hohenberg
W. Kohn

8. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
LDA Kohn-Sham (1965)
W. Kohn
L.J. Sham
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

9. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
FP-LAPW method
Potentiel Muffin-Tin
Interstitial region
Atomic sphere MT Rα
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

10. Results Structural properties
F. El Haj Hassan et al, Phys. Rev. B 73 (2006)

11. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
F. El Haj Hassan et al, Sol.Energy 100 (2014) 1.
Band structure
Eg = 0.03 eV << Eg (experiment)= eV Eg = 1.04 eV
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

12. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
F. El Haj Hassan et al, Sol. Energy 107 (2014) 543.
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

13. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

14. Density of states DOS
Se Ga

15. Results (Electronic properties)
Charge density along the plane (110)
F. El Haj Hassan et al, Phys. Rev. B 81 (2010)

16. Results (Thermodynamic Properties)
Heat capacity & Thermal expansion α T3
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

17. Results (Thermodynamic Properties)
Debye temperature & Grüneisen parameter

18. Conclusions & Perspectives
Applying FP-LAPW to CGS material
GGA is accurate for the structural properties
GGA underestimate the band gap
CGS useful for solar cell technology
Experimental study for the thermal properties
Photoelectronic and optical investigations
Structural phase transitions
Study the Cu(In,Ga)Se2 Alloys
ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015

19. ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015
Thank you for your attention
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ICFPAM’2015, March 30–April 2, Marrakech, Morocco 2015