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Research
My research is to understand fundamental
properties of complex materials using advanced numerical techniques such as
density-functional theory, Monte-Carlo simulation, and (quantum mechanical)
molecular dynamics. I am currently working with Prof. Chris Van de Walle at the University of
California-Santa Barbara (UCSB). My Ph.D. studies (in
Physics) were with Prof. S.
D. Mahanti at Michigan State University (MSU).
Current/recent research projects: (1) Hydrogen storage materials.
(2) Monte Carlo simulation of charge
ordering in a fcc Coulomb lattice
gas. (3) Ab initio studies of
atomic and electronic structures of ternary and quaternary narrow band-gap
semiconductors (with focus on thermoelectric applications). (4) Theory of
defects in narrow band-gap semiconductors (bulk, films, and nanoclusters).
(5) Clustering and nanostructure formation in bulk thermoelectric
materials.
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Partial charge
density associated with (a) hyper-deep and (b) deep defect states created
by an In substitutional impurity in PbTe. These are bonding and
anti-bonding states of In s and
Te p orbitals; see PRB 78, 085111 (2008).
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Highlights
(from our recent publications)
Partial charge
density associated with defect states created by Te vacancies in PbTe
thin films; see PRB 76, 115432
(2007).
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Partial charge density associated with
defect states created by (a) Pb and (b) Te vacancies in PbTe; see PRB 76, 115432 (2007).
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Publications
In
Journals
1. K. Hoang and S. D. Mahanti,
“Electronic structure of Ga-, In-, and Tl-doped PbTe: A supercell study of
the impurity bands,” Physical Review B 78, 085111 (2008). PDF
2. K. Hoang and S. D. Mahanti, “Atomic
and electronic structures of thallium-based III-V-VI2 ternary
chalcogenides: Ab initio
calculations,” Physical
Review B 77, 205107 (2008).
PDF
3. L.-H. Ye, K. Hoang, A. J.
Freeman, S. D. Mahanti, J. He, T. M. Tritt, and M. G. Kanatzidis,
“First-principles study of the electronic, optical and lattice vibrational
properties of AgSbTe2,” Physical Review B 77, 245203 (2008).
PDF
4. M.-K. Han, K. Hoang, H. Kong, P.
Pcionek, C. Uher, K. M. Paraskevopoulos, S. D. Mahanti, and M. G. Kanatzidis,
“Substitution of Bi for Sb and its role in the thermoelectric properties
and nanostructuring in Ag1-xPb18MTe20
(M=Bi, Sb),” Chemistry of Materials 20, 3512 (2008).
5. K. Hoang, S. D. Mahanti, J. R. Salvador,
and M. G. Kanatzidis, “Atomic
ordering and gap formation in Ag-Sb-based ternary chalcogenides,” Physical Review
Letters 99, 156403 (2007).
PDF Related papers (by different research groups):
L.-H. Ye et al. (sx-LDA
calculations), Jovovic and Heremans
(Fermi surface measurements), Barabash et al.
(first-principles cluster expansion)
6. K. Hoang, S. D. Mahanti, and P.
Jena, “Theoretical study of
deep-defect states in bulk PbTe and in thin films,” Physical Review
B 76, 115432 (2007).
PDF
7. S. D. Mahanti, K. Hoang, and S.
Ahmad, “Deep defect states in narrow band-gap semiconductors,” Physica B 401-402C, 291 (2007). PDF
8. J. R. Salvador, K. Hoang, S. D. Mahanti,
and M. G. Kanatzidis, “REAu2In4
(RE = La, Ce, Pr, and Nd): Polyindides from liquid Indium,” Inorganic Chemistry 46, 6933 (2007). PDF
9. S. Ahmad, S. D. Mahanti, K. Hoang,
and M. G. Kanatzidis, “Ab initio studies of the electronic structure of defects in PbTe,” Physical Review
B 74, 155205 (2006). PDF
10. S. Ahmad, K. Hoang, and S. D.
Mahanti, “Ab initio
study of deep defect states in narrow band-gap semiconductors: Group
III impurities in PbTe,” Physical Review Letters 96,
056403 (2006). PDF
11. K. Hoang, K. Desai, and S. D.
Mahanti, “Charge ordering and
self-assembled nanostructures in a fcc Coulomb lattice gas,” Physical Review
B 72, 064102 (2005); selected for the Virtual Journal
of Nanoscale Science and Technology 12 (August
15, 2005). PDF
In
Proceedings
1. S. D. Mahanti, K. Hoang, and S.
Ahmad, “Atomic ordering, electronic structure, and transport properties of
LAST-m systems,” in Thermoelectric Power Generation, edited by T.P.
Hogan, J. Yang, R. Funahashi, and T. Tritt (Mater. Res. Soc. Symp. Proc. 1044,
Warrendale, PA, 2007), 1044-U04-06 (invited).
2. K. Hoang and S. D. Mahanti,
“Defect clustering and nanostructure formation in PbTe-based bulk
thermoelectrics,” in Thermoelectric Power Generation, edited by T.P.
Hogan, J. Yang, R. Funahashi, and T. Tritt (Mater. Res. Soc. Symp. Proc. 1044,
Warrendale, PA, 2007), 1044-U02-08.
3. K. Hoang, S. D.
Mahanti, J. Androulakis, and M. G. Kanatzidis, “Electronic structure of AgPbmSbTem+2
compounds – Implications on thermoelectric properties,” in Materials and
Technologies for Direct Thermal-to-Electric Energy Conversion,
edited by J. Yang, T.P. Hogan, R. Runahashi, and G.S. Nolas (Mater. Res.
Soc. Symp. Proc. 886, Warrendale,
PA, 2006), 0886-F05-06.
4. H. Khang, S. D. Mahanti, B. K.
Rao, and P. Jena, “Magnetic and
thermal properties of interacting (MnxN) clusters,” in Clusters and
Nano-Assemblies: Physical and Biological Systems,
edited by P. Jena, S. N. Khanna, and B. K. Rao, World Scientific,
Singapore, 2005), p. 231.
Others
Ph.D. Thesis: “Atomic
and electronic structures of novel ternary and quaternary narrow band-gap
semiconductors” (200 pages [sorry, couldn’t make it shorter!]).
B.Sc. Thesis [in Vietnamese]: “Độ
tái chuẩn hóa khe dải trong giếng lượng tử
trong gần đúng lưỡng cực plasmon”
(Double plasmon-pole approximation for semiconductor quantum wells at
finite temperatures). PDF
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