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1. Full name: Ho Khac Hieu.
2. Sex: Male
3. Date of birth: 16/10/1984.
4. Place of birth: Quang Tri
5. Admission decision number: 2376/SĐH. Dated 14/12/2006.
6. Changes in academic process: None.
7. Official thesis title: Investigation of the EXAFS cumulants and Debye-Waller factors of crystal and compound semiconductors under influence of temperature and pressure.
8. Major: Theoretical Physics and Mathematical Physics.
9. Code: 62.44.01.01
10. Supervisors:
1. Prof. Dr. sc. Nguyen Van Hung
2. Prof. Dr. Vu Van Hung
11. Summary of the new findings of the thesis:
+ The Anharmonic correlated Einstein model has been applied to study the influence of temperature on EXAFS cumulant of diamond-type semiconductors (Si, Ge) and zinc-blende-type semiconductors (GaAs, GaP, GaSb, InAs, InP và InSb). Using Morse and Stillinger-Weber potential, we found out the analytical expressions of the temperature dependence of the first, the second and the third EXAFS cumulants of semiconductors.
+ The Anharmonic correlated Einstein model has been developed to investigate the pressure dependence of EXAFS cumulants. The general expressions of pressure dependent-EXAFS cumulants have been derived.
+ The Statistical moment method has been developed to study the EXAFS cumulants. Using the statistical moment method, analytical expressions of the first and second EXAFS cumulants have been derived.
+ Using those above results, numerical calculations of temperature and pressure dependent EXAFS cumulants have been performed for a series of zinc-blende-type semiconductors and Cu, Kr. It shows the agreement between our results and experimental data as well as other theoretical calculations.
+ We also found out the analytical expressions and performed the numerical calculations of compressibility, mean-square displacement,… of diamond-type and zinc-blende-type semiconductors.
12. Practical applicability, if any:
+) This doctoral thesis is the theoretical basis in investigation the thermodynamic properties and EXAFS of crystallize and compound semiconductors under influence of temperature and pressure.
+) It gives the direction for experiment on manufacturing the semiconductor materials under influence of temperature and pressure.
13. Further research directions:
+ Investigation the influence of temperature and pressure on cumulants of low-dimensional semiconductor systems as quantum well, quantum wire, and quantum dot,…
+ Calculation of perpendicular mean-square relative displacements of materials.
14. Thesis-related publications:
[1] Vu Van Hung, Ho Khac Hieu and K. Masuda-Jindo (2010), “Study of EXAFS cumulants of crystals by the statistical moment method and anharmonic correlated Einstein model”, Comput. Mater. Sci. 49 (4), pp. S214-S217.
[2] Nguyen Van Hung, Vu Van Hung, Ho Khac Hieu and Ronald R. Frahm (2011), “Pressure effects in Debye-Waller factors and in EXAFS”, Physica B: Condens. Matter 406 (3), pp. 456-460.
[3] Ho Khac Hieu and Vu Van Hung (2011), “Study of thermodynamic properties of zinc-blende-type semiconductors: temperature and pressure dependences”, Mod. Phys. Lett. B. 25 (12 & 13), pp.1041–1051.
[4] Ho Khac Hieu and Vu Van Hung (2010), “Investigation of extended X-ray absorption Fine structure cumulants of diamond-type germanium crystal: temperature dependence”, Jour. Sci. HNUE 55 (1), pp. 26-31.
[5] Vu Van Hung, Ho Khac Hieu, Nguyen Van Hung (2010), “Pressure Dependence of EXAFS Debye-Waller Factor in Crystals”, Comm. in Phys. 20 (3), pp. 219-225.
[6] Vu Van Hung and Ho Khac Hieu (2011), “Study the temperature dependence of EXAFS cumulants of Si and Ge by the anharmonic correlated Einstein model”, Comm. in Phys. Vol. 21, No. 1. (In press).
[7] Ho Khac Hieu, Vu Van Hung and Nguyen Van Hung (2011), “Temperature dependence of thermodynamic quantities of zinc-blende semiconductors investigated by statistical moment method”, VNU. Journal of Science. (In press).
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