Urushiyama Hironao, Morito Haruhiko, Yamane Hisanori, Terauchi Masami
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University 2-1-1 Katahira, Aoba-ku Sendai 980-8577 Japan.
Institute for Materials Research, Tohoku University 2-1-1 Katahira, Aoba-ku Sendai 980-8577 Japan
RSC Adv. 2018 Dec 4;8(71):40505-40510. doi: 10.1039/c8ra07971d.
Single crystals of a Na-Ga-Si clathrate, NaGaSi, of size 2.9 mm were grown the evaporation of Na from a Na-Ga-Si melt with the molar ratio of Na : Ga : Si = 4 : 1 : 2 at 773 K for 21 h under an Ar atmosphere. The crystal structure was analyzed using X-ray diffraction with the model of the type-I clathrate (cubic, = 10.3266(2) Å, space group 3̄, no. 223). By adding Sn to a Na-Ga-Si melt (Na : Ga : Si : Sn = 6 : 1 : 2 : 1), single crystals of NaGa Si ( = 4.94-5.52, = 10.3020(2)-10.3210(3) Å), with the maximum size of 3.7 mm, were obtained Na evaporation at 723-873 K. The electrical resistivities of NaGaSi and NaGaSi were 1.40 and 0.72 mΩ cm, respectively, at 300 K, and metallic temperature dependences of the resistivities were observed. In the Si L soft X-ray emission spectrum of NaGaSi, a weak peak originating from the lowest conduction band in the undoped Si was observed at an emission energy of 98 eV.
通过在氩气气氛下，于773K使摩尔比为Na : Ga : Si = 4 : 1 : 2的Na - Ga - Si熔体中钠蒸发21小时，生长出尺寸为2.9毫米的Na - Ga - Si包合物NaGaSi单晶。使用X射线衍射并采用I型包合物模型（立方晶系， = 10.3266(2) Å，空间群3̄，编号223）对晶体结构进行了分析。通过向Na - Ga - Si熔体（Na : Ga : Si : Sn = 6 : 1 : 2 : 1）中添加Sn，在723 - 873K下通过钠蒸发获得了尺寸最大为3.7毫米的NaGa Si单晶（ = 4.94 - 5.52， = 10.3020(2) - 10.3210(3) Å）。在300K时，NaGaSi和NaGaSi的电阻率分别为1.40和0.72 mΩ·cm，并且观察到电阻率具有金属性的温度依赖性。在NaGaSi的Si L软X射线发射光谱中，在98eV的发射能量处观察到一个源自未掺杂Si中最低导带的弱峰。
