Bai Xiaojing, Xue Yuanbin, Luo Kan, Chen Ke, Huang Qing, Zha Xian-Hu, Du Shiyu
School of Materials Science and Engineering, Anyang Institute of Technology, Anyang, Henan455000, China.
School of Chemistry and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan455000, China.
ACS Omega. 2022 Nov 7;7(45):40929-40940. doi: 10.1021/acsomega.2c03964. eCollection 2022 Nov 15.
As a large family of two-dimensional materials, MXenes have attracted intensive attention in recent years. For more functional applications, it is of great significance to determine new MXene members. Here, we theoretically expand the M elements of MXenes to the lanthanide series. Based on density functional theory calculations, the bare lanthanide-based carbides MC (M = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) and the corresponding fluorine- and hydroxyl-terminated configurations are investigated. Most of the fluorine- and hydroxyl-terminated MXenes investigated are half-metals. Specifically, in the half-metallic EuCF, the spin-down states show a band gap larger than 2 eV, implying this configuration's potential applications in spin generation and injection. Both GdCT (T = F and OH) are magnetic semiconductors. The former shows an indirect band gap of 1.38 eV, while the latter presents a direct one of 0.882 eV. These two configurations also show large magnetic moments higher than 13.7 μ per unit cell. All the hydroxyl-terminated MXene members show relatively low work functions, with the lowest value of 1.46 eV determined in TmC(OH). These predicted electronic properties imply that the lanthanide-based MXenes could have potential applications in spintronics, information storage, near-infrared detectors, field effect transistors, and field emitter cathodes.
作为二维材料的一个大家族，MXenes近年来受到了广泛关注。为了实现更多功能应用，确定新的MXene成员具有重要意义。在此，我们从理论上将MXenes的M元素扩展到镧系元素。基于密度泛函理论计算，研究了裸露的镧系碳化物MC（M = Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm和Yb）以及相应的氟端基和羟基端基构型。所研究的大多数氟端基和羟基端基MXenes都是半金属。具体而言，在半金属EuCF中，自旋向下态的带隙大于2 eV，这意味着该构型在自旋产生和注入方面具有潜在应用。GdCT（T = F和OH）都是磁性半导体。前者显示出1.38 eV的间接带隙，而后者呈现出0.882 eV的直接带隙。这两种构型还显示出高于每晶胞13.7 μ的大磁矩。所有羟基端基的MXene成员都表现出相对较低的功函数，在TmC(OH)中确定的最低值为1.46 eV。这些预测的电子特性表明，基于镧系元素的MXenes在自旋电子学、信息存储、近红外探测器、场效应晶体管和场发射阴极方面可能具有潜在应用。
