反铁磁状态层状Co基复合氧化物Ca_2Co_2O_5电子学性质的研究
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摘要
基于密度泛函理论方法分析研究了一种低自旋反铁磁状态Co基层状复合氧化物Ca_2Co_2O_5的电子学性质。结果表明,其能带中均包括5个子带,其中费米能级附近的能带中的能级数量较多,具有较宽的分布。向上自旋的电子形成半导体型能带,带宽为0.0112 eV,向下自旋的电子形成金属型能带。在费米能级附近,s、p、d电子对其态密度的贡献程度逐渐提高。CaCoO层对总态密度贡献较大,CoO层对总态密度贡献较小。Ca中电子主要在远离费米能的位置形成能带,Co中电子主要在费米能附近形成能带,O中电子主要在-19 eV和费米能形成能带,Co d电子和O p电子贡献这种反铁磁状态层状Co基复合氧化物Ca_2Co_2O_5的电子学性质。
The electronical properties of a kind of anti-ferromagnetic Co-based layered compound oxide Ca_2 Co_2 O_5 are investigated by the density functional theory method. The results show that there are five sub-bands for spin up and down electrons, and there are many energy bands near Fermi energy which show wider allocation. The spin up electrons forms semiconductor type band structure with indirect band gap of 0.0112 eV, nevertheless the spin down electrons forms the metallic band structure. The contribution of s state electrons to density of states is the least, that of p state electrons is in the middle, while d state electrons contribute the most. The electrons of the CaCoO sub-layer contribute to the system much more than that of the electrons of CoO sub-layer. The Ca electrons contribute to density of state far from Fermi level,the Co electrons contribute to density of states near Fermi level, and the O electrons form bands near Fermi level as well as-19 eV. The Co d and O p electrons contribute to electronic properties of the anti-ferromagnetic Co-based layered oxide Ca_2 Co_2 O_5.
The electronical properties of a kind of anti-ferromagnetic Co-based layered compound oxide Ca_2 Co_2 O_5 are investigated by the density functional theory method. The results show that there are five sub-bands for spin up and down electrons, and there are many energy bands near Fermi energy which show wider allocation. The spin up electrons forms semiconductor type band structure with indirect band gap of 0.0112 eV, nevertheless the spin down electrons forms the metallic band structure. The contribution of s state electrons to density of states is the least, that of p state electrons is in the middle, while d state electrons contribute the most. The electrons of the CaCoO sub-layer contribute to the system much more than that of the electrons of CoO sub-layer. The Ca electrons contribute to density of state far from Fermi level,the Co electrons contribute to density of states near Fermi level, and the O electrons form bands near Fermi level as well as-19 eV. The Co d and O p electrons contribute to electronic properties of the anti-ferromagnetic Co-based layered oxide Ca_2 Co_2 O_5.
引文
[1] Vidyasagar K, Gopalakrishnan J, Rao C N R. A convenient route for the synthesis of complex metal oxides employing[J]. Inorganic Chemistry, 1984, 23:1206-1210.
[2] Xu J, Zhao X B, Zhu T J, et al. Thermoelectric properties of boron doped SiGe alloys by ball milling[J]. Journal of Materials Science and Engineering(材料科学与工程学报), 2017, 35:173(in Chinese).
[3] Xing Z B, Li J F. Powder metallurgic synthesis of mid-temperature lead-free AgSn_(18)SbTe_(20)thermoelectric materials and processing influence on thermoelectric performance[J]. Journal of Inorganic Materials(无机材料学报),2015, 30:872(in Chinese).
[4] Ma R Q, Qian Y, Xu Y Y, et al. Preparation and study on magnetic properties of Fe doped Ca_3Co_4O_(9+δ)[J].Natural Sciences Journal of Hrbin Normal University(哈尔滨师范大学自然科学学报),2015, 31:97-99(in Chinese).
[5] Zong P A,Chen L D. Preparation and mechanical properties of Ce_(0.85)Fe_3CoSb_(12/r)GO thermoelectric nanocomposite[J]. Journal of Inorganic Materials(无机材料学报),2017, 32:33(in Chinese).
[6] Funahashi R, Nakamura T, Kageyama K, et al. Monolithic oxide-metal composite thermoelectric generators for energy harvesting[J]. Journal of Applied Physics, 2011, 109:124509.
[7] Funahashi R, Matsubara I, Ikuta H, et al. An oxide single crystal with high thermoelectric performance in air[J]. Japanese Journal of Applied Physics, 2000, 39:L1127.
[8] Shikano M, Funahashi R. Electrical and Thermal properties of single-crystalline(Ca2CoO_3)_(0.7)CoO_2 with a Ca3Co_4O_9 structure[J]. Applied Physics Letters, 2003, 82:1851.
[9] Masset A C, Michel C, Maignan A, et al. Misfit-layered cobaltite with an anisotropic giant magnetoresistance:Ca3Co_4O_9[J]. Physical Review B, 2000, 62:166-175.
[10] Zhang F P, Lu Q M, Zhang X, et al. First principle investigation of electronic structure of CaMnO_3 thermoelectric compound oxides[J]. Journal of Alloys and Compounds, 2011, 509:542.
[11] Zhang F P, Lu Q M, Zhang X, et al. Electrical transport properties of CaMnO_3 thermoelectric compound:A theoretical study[J]. Journal of Physics and Chemistry of Solids, 2013, 74:1859.
[12] Xu G Y,Zou P,Wang S,et al. Effects of Annealing temperature on Bi2Te_(2.7)Se_(0.3)doped with Gd fabricated by high pressure sintering[J]. Rare Metal Materials and Engineering(稀有金属材料与工程),2015, 44:950(in Chinese).
[13] Zhao Y Q, Wu L J, Liu B, et al. Tuning superior solar cell performance of carrier mobility and absorption in perovskite CH_3NH_3GeCl_3:A density functional calculations[J]. Journal of Power Sources, 2016, 313:96.
[14] Zhang Z W, Wang X Y, Liu Y J, et al. Development on thermoelectric materials[J]. Journal of the Chinese Ceramic Sciety(硅酸盐学报),2018, 46:288(in Chinese).
[2] Xu J, Zhao X B, Zhu T J, et al. Thermoelectric properties of boron doped SiGe alloys by ball milling[J]. Journal of Materials Science and Engineering(材料科学与工程学报), 2017, 35:173(in Chinese).
[3] Xing Z B, Li J F. Powder metallurgic synthesis of mid-temperature lead-free AgSn_(18)SbTe_(20)thermoelectric materials and processing influence on thermoelectric performance[J]. Journal of Inorganic Materials(无机材料学报),2015, 30:872(in Chinese).
[4] Ma R Q, Qian Y, Xu Y Y, et al. Preparation and study on magnetic properties of Fe doped Ca_3Co_4O_(9+δ)[J].Natural Sciences Journal of Hrbin Normal University(哈尔滨师范大学自然科学学报),2015, 31:97-99(in Chinese).
[5] Zong P A,Chen L D. Preparation and mechanical properties of Ce_(0.85)Fe_3CoSb_(12/r)GO thermoelectric nanocomposite[J]. Journal of Inorganic Materials(无机材料学报),2017, 32:33(in Chinese).
[6] Funahashi R, Nakamura T, Kageyama K, et al. Monolithic oxide-metal composite thermoelectric generators for energy harvesting[J]. Journal of Applied Physics, 2011, 109:124509.
[7] Funahashi R, Matsubara I, Ikuta H, et al. An oxide single crystal with high thermoelectric performance in air[J]. Japanese Journal of Applied Physics, 2000, 39:L1127.
[8] Shikano M, Funahashi R. Electrical and Thermal properties of single-crystalline(Ca2CoO_3)_(0.7)CoO_2 with a Ca3Co_4O_9 structure[J]. Applied Physics Letters, 2003, 82:1851.
[9] Masset A C, Michel C, Maignan A, et al. Misfit-layered cobaltite with an anisotropic giant magnetoresistance:Ca3Co_4O_9[J]. Physical Review B, 2000, 62:166-175.
[10] Zhang F P, Lu Q M, Zhang X, et al. First principle investigation of electronic structure of CaMnO_3 thermoelectric compound oxides[J]. Journal of Alloys and Compounds, 2011, 509:542.
[11] Zhang F P, Lu Q M, Zhang X, et al. Electrical transport properties of CaMnO_3 thermoelectric compound:A theoretical study[J]. Journal of Physics and Chemistry of Solids, 2013, 74:1859.
[12] Xu G Y,Zou P,Wang S,et al. Effects of Annealing temperature on Bi2Te_(2.7)Se_(0.3)doped with Gd fabricated by high pressure sintering[J]. Rare Metal Materials and Engineering(稀有金属材料与工程),2015, 44:950(in Chinese).
[13] Zhao Y Q, Wu L J, Liu B, et al. Tuning superior solar cell performance of carrier mobility and absorption in perovskite CH_3NH_3GeCl_3:A density functional calculations[J]. Journal of Power Sources, 2016, 313:96.
[14] Zhang Z W, Wang X Y, Liu Y J, et al. Development on thermoelectric materials[J]. Journal of the Chinese Ceramic Sciety(硅酸盐学报),2018, 46:288(in Chinese).