我院教师近期在Journal of Power Sources、Physical Review B、Physical Chemistry Chemical Physics、中国物理B、物理学报等专业学术期刊上发表系列论文
Yingbin Lin(林应斌), Yanmin Yang(杨艳敏), Ruibing Yu(余蕊冰,硕士生), Heng Lai(赖恒), Zhigao Huang(黄志高), Enhanced electrochemical performances of LiNi0.5Mn1.5O4 by surface modification with superconducting YBa2Cu3O7, Journal of Power Sources, Volume 259, 1 August 2014, Pages 188-194.
Abstract
LiNi0.5Mn1.5O4 modified with superconducting YBa2Cu3O7 (YBCO) is synthesized by mixing as-prepared LiNi0.5Mn1.5O4 powders and the sol–gel-driven YBa2Cu3O7 matrix, subsequently followed by high-temperature calcinations. The effect of YBCO-modification on the electrochemical performances of LiNi0.5Mn1.5O4@YBCO cells in a wide operation temperature is investigated systematically by the charge/discharge testing, cyclic voltammograms and AC impedance spectroscopy, respectively. In comparison with the pristine LiNi0.5Mn1.5O4, LiNi0.5Mn1.5O4@YBCO samples exhibit higher capacity, better cyclability and higher rate capability in a wide operation temperature range. An analysis of the electrochemical measurements reveals that the improved performance of LiNi0.5Mn1.5O4@YBCO is due to the better electric contact among particles, much lower charge-transfer resistances and higher lithium diffusion rate, especially at low temperature. In addition, the homogeneous YBCO layer formed on the LiNi0.5Mn1.5O4 protects the active materials from chemical attack by HF, which suppresses the dissolution of Ni or Mn from LiNi0.5Mn1.5O4 in the LiPF6 based electrolyte.
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Journal of Power Sources 259, 188-194 (2014).pdf
Jian-Min Zhang(张健敏), Wenmei Ming, Zhigao Huang(黄志高), Gui-Bin Liu, Xufeng Kou, Yabin Fan, Kang L. Wang, and Yugui Yao, Stability, electronic, and magnetic properties of the magnetically doped topological insulators Bi2Se3, Bi2Te3, and Sb2Te3, Phys. Rev. B 88, 235131 – Published 30 December 2013
ABSTRACT
Magnetic interaction with the gapless surface states in a topological insulator (TI) has been predicted to give rise to a few exotic quantum phenomena. However, the effective magnetic doping of TI is still challenging in the experiment. Using first-principles calculations, the magnetic doping properties (V, Cr, Mn, and Fe) in three strong TIs (Bi2Se3, Bi2Te3, and Sb2Te3) are investigated. We find that for all three TIs the cation-site substitutional doping is most energetically favorable with the anion-rich environment as the optimal growth condition. Further, our results show that under the nominal doping concentration of 4%, Cr- and Fe-doped Bi2Se3, Bi2Te3, and Cr-doped Sb2Te3 remain as insulators, while all the V- and Mn-doped TIs, and Fe-doped Sb2Te3 become metal. We also show that the magnetic interaction of Cr-doped Bi2Se3 tends to be ferromagnetic, while Fe-doped Bi2Se3 is likely to be antiferromagnetic. Finally, we estimate the magnetic coupling and the Curie temperature for the promising ferromagnetic insulator (Cr-doped Bi2Se3) by Monte Carlo simulation. These findings may provide important guidance for the magnetism incorporation in TIs experimentally.
本网全文下载：Phys. Rev. B 88, 235131 (2013).pdf
Zhensheng Hong(洪振生), Hong Dai, Zhigao Huang(黄志高) and Mingdeng Wei, Understanding the growth and photoelectrochemical properties of mesocrystals and single crystals: a case of anatase TiO2, Phys. Chem. Chem. Phys., 2014,16, 7441-7447.
Abstract
Anatase TiO2 mesocrystals and single crystals with dominant {101} facets were successfully synthesized without any additives using titanate nanowires as precursors under solvothermal and hydrothermal conditions, respectively. It is proposed that the oriented self-assembly process for the formation of TiO2 mesocrystals was controlled by the same thermodynamic principle as that of single crystals in this simple reaction system. Furthermore, the TiO2 mesocrystals were applied in photoelectrochemical (PEC) water splitting and demonstrated much enhanced photocurrent, almost 191% and 274% compared with that of TiO2 single crystals and commercial P25, respectively. Electrochemical impedance measurements under illumination revealed that the photocurrent increase was largely ascribed to the effective charge separation of electron–hole pairs and fast interfacial charge transfer. This could be attributed to the intrinsic characteristics of the mesostructured TiO2 composed of highly oriented nanocrystal subunits offering few grain boundaries, nanoporous nature and a short transport distance.
本网全文下载：Phys. Chem. Chem. Phys. 16, 7441-7447 (2014).pdf
Tang Ke-Qin (汤可嵚,硕士生), Zhong Ke-Hua (钟克华), Cheng Yan-Ming (程燕铭,硕士生) and Huang Zhi-Gao (黄志高), Effect of Gd doping on the magnetism and work function of Fe1—xGdx/Fe (001), Chinese Physics B, Volume 23, Number 5, 056301 (2004).
Abstract
The magnetism and work function Φ of Fe1—xGdx/Fe (001) films have been investigated using first-principles methods based on the density functional theory. The calculated results reveal that Gd doping on the Fe (001) surface would greatly affect the geometrical structure of the system. The restruction of the surface atoms leads to the transition of magnetic coupling between Gd and Fe atoms from ferromagnetic (FM) for 0.5 ≤ x ≤ 0.75 to antiferromagnetic (AFM) for x = 1.0. For Fe1—xGdx/Fe (001) (x = 0.25, 0.5, 0.75, 1.0), the charge transfer from Gd to Fe leads to a positive dipole formed on the surface, which is responsible for the decrease of the work function. Moreover, it is found that the magnetic moments of Fe and Gd on the surface layer can be strongly influenced by Gd doping. The changes of the work function and magnetism for Fe1—xGdx/Fe (001) can be explained by the electron transfer, the magnetic coupling interaction between Gd and Fe atoms, and the complex surface restruction. Our work strongly suggests that the doping of the metal with a low work function is a promising way for modulating the work function of the magnetic metal gate.
本网全文下载：Chinese Physics B 23(5), 056301 (2014).pdf
谢玲玲(硕士生), 陈水源, 刘凤金(硕士生), 张建敏, 林应斌, 黄志高, Zn0.97Cr0.03O的PLD制备及其铁磁性, 物理学报, 2014, Vol. 63, Issue (7): 077102.
摘要： 采用脉冲激光沉积（PLD）的方法在石英基片上制备了不同氧分压（0，0.05，0.15和0.20 Pa）下Zn0.97Cr0.03O薄膜，并测量了它们的磁性、XRD谱、PL谱及XPS谱等. 实验结果表明，所有的样品都具有良好的结晶性，且都沿c轴高度取向；磁测量结果表明，四个样品都具有铁磁性，且在氧压为0.15 Pa下沉积的薄膜磁性最强；四个样品都存在VZn，Oi，Zni，VZn-，VO缺陷，尤其是VZn对应共振峰面积占所有缺陷总面积的百分比和样品的饱和磁化强度具有相同的变化趋势，表明Zn0.97Cr0.03O磁性与锌空位密切相关；四个样品中都存在Cr3+离子，且在0.15 Pa时Cr3+的含量最多. 上述实验结果表明，Cr3+和VZn的缺陷复合体是ZnO：Cr样品具有稳定的铁磁有序的最有利条件，它证实了早先的基于第一性原理的计算结果.
本网全文下载：物理学报 63(7), 077102 (2014).pdf
