Atuchin V V, Liang Fei, Grazhdannikov S, Isaenko L I, Krinitsin P G, Molokeev M S, Prosvirin I P, Jiang Xingxing, Lin Zheshuai
Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS Novosibirsk 630090 Russia
Laboratory of Semiconductor and Dielectric Materials, Novosibirsk State University Novosibirsk 630090 Russia.
RSC Adv. 2018 Mar 12;8(18):9946-9955. doi: 10.1039/c8ra01079j. eCollection 2018 Mar 5.
The LiGaTe crystals up to 5 mm in size were grown by the modified Bridgman-Stockbarger technique and the cell parameter dependence on temperature in the range of 303-563 K was evaluated by the X-ray diffraction analysis. The thermal behavior of LiGaTe is evidently anisotropic and a negative thermal expansion is found along crystallographic direction with coefficient -8.6 × 10. However, the normal thermal expansion in two directions with coefficient 19.1 × 10 is dominant providing unit cell volume increase on heating. The atomic mechanism is proposed to describe this pronounced anisotropic expansion effect. The electronic structure of LiGaTe is measured by X-ray photoelectron spectroscopy and the band structure is obtained by DFT calculations. The pressure response from 0 to 5 GPa was calculated and a normal crystal compression is found. This work indicates that LiGaTe is promising as an IR NLO or window material for many practical applications because the thermal expansion coefficients of this telluride are not big. We believe that these results would be beneficial for the discovery and exploration of new IR optoelectronic polyfunctional metal tellurides.
采用改进的布里奇曼-斯托克巴杰技术生长出尺寸达5毫米的LiGaTe晶体，并通过X射线衍射分析评估了303 - 563 K范围内晶胞参数对温度的依赖性。LiGaTe的热行为明显具有各向异性，沿晶体学方向发现了负热膨胀，系数为 -8.6×10 。然而，在另外两个方向上系数为19.1×10的正常热膨胀占主导，导致加热时晶胞体积增加。提出了原子机制来描述这种明显的各向异性膨胀效应。通过X射线光电子能谱测量了LiGaTe的电子结构，并通过密度泛函理论计算得到了能带结构。计算了0至5 GPa的压力响应，发现晶体正常压缩。这项工作表明，LiGaTe有望作为红外非线性光学或窗口材料用于许多实际应用，因为这种碲化物的热膨胀系数不大。我们相信这些结果将有助于发现和探索新型红外光电子多功能金属碲化物。
