Thanomngam, Pitiporn

Loading...
Thumbnail Image
Preferred name
Thanomngam, Pitiporn
Alternative Name
Thanomngam, P.
Thanomngam, Pittiporn
Main Affiliation
Email
pitiporn.th@kmitl.ac.th

Settings

Now showing 1 - 5 of 5
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    First-principles investigation on elastic constants of TiN under high pressure
    (2013-10-29)
    Prasert, Kittiya
    ;
    Thanomngam, Pitiporn
    ;
    Sarasamak, Kanoknan
    Elastic constants of NaCl-type TiN under pressure were investigated by first-principles calculations within both local density approximation (LDA) and Perdew-Burke-Ernzerhof generalized-gradient approximation (PBE-GGA). At ambient pressure, the calculated lattice parameter, bulk modulus, and elastic constants of NaCl-type TiN are in well agreement with other available values. Under pressure, all elastic constants, C<inf>11</inf>, C<inf>12</inf>, and C<inf>44</inf>, are found to increase with pressure. C<inf>11</inf>, which is related to the longitudinal distortion, increases rapidly with pressure while C<inf>12</inf> and C<inf>44</inf> which are related to the transverse and shear distortion, respectively, are much less sensitive to pressure. © (2013) Trans Tech Publications, Switzerland.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    First-Principles Investigation on Structural and Electronic Properties of Ferromagnetic Fe2P4O12
    (2015-06-23)
    Rerksompus, Pathompong
    ;
    Sarasamak, Kanoknan
    ;
    Boonchom, Banjong
    ;
    Thanomngam, Pitiporn
    Structural and electronic properties of Fe<inf>2</inf>P<inf>4</inf>O<inf>12</inf> have been investigated using first-principles calculation technique. The results indicated that the Fe<inf>2</inf>P<inf>4</inf>O<inf>12</inf> structure is monoclinic of C<inf>2</inf>/c with lattice parameters of a = 12.228 Å, b = 8.530 Å, c = 9.835 Å and β = 118.67°. Two nonequivalent octahedral FeO<inf>6</inf> from the calculation have an average Fe-O distance of 2.143 Å. Both FeO<inf>6</inf> are dominated by covalent interactions assigned to Fe<inf>3d</inf> and O<inf>2p</inf> at the valent electronic states. The DOS calculation gives well explanation on its half-metallic ferromagnetic property. These results are in very good agreement with the previous experimental reports. © 2015
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    First-principles study of antisite defects in orthorhombic PbZrO 3
    (2014-09-02)
    Chotsawat, Maneerat
    ;
    Sarasamak, Kanoknan
    ;
    Thanomngam, Pitiporn
    ;
    T-Thienprasert, Jiraroj
    First-principles calculations based on density functional theory (DFT) within local density approximation were employed to investigate the antisite defects, including Pb<inf>Zr</inf> and Zr<inf>Pb</inf>, in orthorhombic PbZrO<inf>3</inf> by determining their defect formation energies. The formation energies of antisite defects were then compared with those of other dominant defects, i.e., lead Pb, zirconium Zr, and oxygen O vacancies to examine the likelihood of their existence. Our results revealed that Pb<inf>Zr</inf> defect in neutral charge state is the most dominant defect under O-rich or oxidizing condition in agreement with the previous work. In addition, there is a little structural relaxation when the Zr atom is replaced by Pb atom to form Pb <inf>Zr</inf> defect in neutral charge state. In opposite, under O-poor or reducing condition, the formation energies of antisite defects are quite high and higher than those of vacancy defects. This suggests that antisite defects are unlikely to form under reducing condition. © 2014 Taylor & Francis Group, LLC.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    First-principles study of Bi and Al in orthorhombic PbZrO3
    (2016-04-01)
    Chotsawat, Maneerat
    ;
    Sarasamak, Kanoknan
    ;
    Thanomngam, Pitiporn
    ;
    Limpijumnong, Sukit
    ;
    T-Thienprasert, Jiraroj
    Lead zirconate PbZrO<inf>3</inf> (PZO) is one of the most important ceramic materials due to its antiferroelectric property, which can be used in many technological applications. Due to the toxicity of Pb, there is an attempt to replace Pb with other non-toxic elements. It has been reported that doping orthorhombic-PZO with Bi and Al atoms could stabilize the antiferroelectric property in a wide temperature range and reduce the lead content in the material. In this work, we used first-principles calculations based on density functional theory to investigate the microscopic and electronic structures of Bi and Al defects in orthorhombic-PZO. Our calculated defect formation energies revealed that Bi atom can substitute on either Pb site (A-site) or Zr site (B-site); depending on the Fermi-level as well as the crystal growth condition. On the other hand, Al atom is likely to substitute only on the Zr site. In addition, our calculations revealed that there is only a small binding between Bi<inf>Pb</inf> and adjacent Al<inf>Zr</inf> or Bi<inf>Zr</inf> with the binding energies of ∼0.2 eV. This indicates that Bi<inf>Pb</inf> and Al<inf>Zr</inf> (or Bi<inf>Zr</inf>) are unlikely to form complexes.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    First principles calculations on crystal and electronic structure of Co2P4O12
    (2014-09-02)
    Rerksompus, Pathompong
    ;
    Sarasamak, Kanoknan
    ;
    Boonchom, Banjong
    ;
    Thanomngam, Pitiporn
    Crystal and electronic structure of violet-pink Co<inf>2</inf>P <inf>4</inf>O<inf>12</inf> have been investigated using first principles calculations based on density functional theory. Its theoretical X-ray diffraction and X-ray absorption fine structure spectra were calculated and compared with their experimental spectra to verify its monophasic. The calculated spectra are in good agreement with the experimental data giving parameters of a = 11.993 Å, b = 8.328 Å, c = 10.150 Å and β = 118.51°. Our calculations on band structure and density of states of Co<inf>2</inf>P<inf>4</inf>O<inf>12</inf> showed that its major electronic transition is associated with internal Co-3d. The calculations indicated that Co<inf>2</inf>P<inf>4</inf>O<inf>12</inf> is a half metal ferromagnetic material which disagreed with the experimental knowledge. © 2014 Taylor & Francis Group, LLC.
      1