新型层状铽氮氯化物的合成和电子结构

Synthesis and Electronic Structure of New Layered Tb Nitride Chlorides

利用纯金属铽和NH_4Cl粉末,通过高温气固相合成法,成功合成了新型层状铽氮氯化物,并通过粉末X射线衍射进行了结构表征,分析结果表明,反应合成物为两种新的层状结构晶体,分别为α-CeNCl结构的α-TbNCl相(空间群为P4/nmm)和另一种未发现过的四方(TbN)2Cl层状相(空间群为P4mm)。第一性原理计算结果表明,(TbN)_2Cl和α-TbNCl都属于没有能隙的坏金属,费米能级主要由未满的4f电子带占据,因此稀土元素4f电子对体系的电子性质可能有较大的影响。

In this paper,by using the method of gas- solid phase reaction at high temperature,new layered rare earth materials have been synthesized for the first time. The phase structure was characterized by powder X- ray diffraction,the analysis results show that the compound contains two new layered structure phases. The phase of α- TbNCl has the same crystalline structure ocuppying the phase of α- Ce NCl,which crystallized in a tetragonal structure with space group P4 / nmm（ No. 129）,another new stable phase（ TbN）2Cl was also synthesized,which belongs to a tetragonal system with P4 mm space group（ No. 99）. The results of the first- principles calculations show that phases of（ TbN）2Cl and α- TbNCl are all belong to bad metals without energy gap,the density of state of non- filled band 4f electrons appears near the Fermi level,consequently,the unique 4f electrons of rare earth in compound are probably critical to their electronic properties.