Geometrical, Electronic and Magnetic Properties of MgH2: Influence of Charged Defects

F. GAZTAÑAGA; CARLA R. LUNA; M. SANDOVAL; C. MACCHI; P. JASEN

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2016 vol. 120 p. 22844 - 22851

1932-7447

<!-- /* Font Definitions */@font-face{font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-520092929 1073786111 9 0 415 0;}@font-face{font-family:AdvGulliv-R;panose-1:0 0 0 0 0 0 0 0 0 0;mso-font-alt:"MS Mincho";mso-font-charset:128;mso-generic-font-family:auto;mso-font-format:other;mso-font-pitch:auto;mso-font-signature:0 134676480 16 0 131072 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;margin-left:0cm;line-height:115%;mso-pagination:widow-orphan;font-size:11.0pt;font-family:Calibri;mso-fareast-font-family:Calibri;mso-bidi-font-family:"Times New Roman";mso-ansi-language:ES-AR;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:10.0pt;mso-ansi-font-size:10.0pt;mso-bidi-font-size:10.0pt;font-family:Calibri;mso-ascii-font-family:Calibri;mso-fareast-font-family:Calibri;mso-hansi-font-family:Calibri;}@page WordSection1{size:612.0pt 792.0pt;margin:72.0pt 90.0pt 72.0pt 90.0pt;mso-header-margin:36.0pt;mso-footer-margin:36.0pt;mso-paper-source:0;}div.WordSection1{page:WordSection1;}-->A study on the effect of the presence of charged vacancy on the electronic and magnetic properties of perfect magnesium hydride is presented. To this aim spin polarized ab-initio calculations for the MgH2 structure containing a H vacancy or a Mg vacancy or a H-Mg di-vacancy were used. For each case three possible charge states (q = +1, 0 and −1) were taken into account. The calculated parameters were the vacancy formation energy, band gap, magnetic moment, Fermi level position with respect to the top of the valence band and the bottom of the conduction band and density of states curves. From the calculations, it was found that positive and negative charged H vacancies and the negative charged divacancy are the most probable formed defects.Besides the presence of a negative or neutral H vacancy produces to an important reduction of the band gap, which should improve the semiconductor behavior of the material. Furthermore the charged H vacancies provoke an important local rearrangement in the structure of the hydride. On the other hand, the positive charged Mg vacancy induces the highest magnetic moment.