Hernández-Vázquez E E, López-Moreno S, Munoz F, Ricardo-Chavez J L, Morán-López J L
Centro Nacional de Supercómputo, IPICYT Camino a la Presa San José 2055, Col. Lomas 4a sección San Luis Potosí S.L.P. 78216 Mexico.
CONACYT - División de Materiales Avanzados, IPICYT Camino a la Presa San José 2055, Col. Lomas 4a sección San Luis Potosí S.L.P. 78216 Mexico
RSC Adv. 2021 Sep 20;11(49):31073-31083. doi: 10.1039/d1ra05714f. eCollection 2021 Sep 14.
A theoretical study of the Mn trimer adsorbed on the noble metal surfaces Au(111) and Cu(111) is reported. The calculations were performed using first-principles methods within the density functional theory and the generalized gradient approximation in the collinear and non-collinear magnetic phases. The system was modeled by considering a surface unit cell of 25 atoms to improve the trimer's isolation on the surface. We evaluated the trimer as a linear chain and forming triangular structures. The triangular trimer can be adsorbed in two possible configurations, above an empty surface triangle site (Δ) or on a triangle with a surface atom at the center in a hexagonal structure (H). The difference is the coordination of the Mn with surface atoms. We studied the antiferromagnetic (AF), ferromagnetic (FM), and non-collinear (NC) magnetic cases. As a result, the lowest energy configuration on both metals is the AF configuration, which has an isosceles triangle shape. In comparison, the NC and the FM configurations adopt an equilateral geometry. The same trend was observed for the H configurations, but they are less bonded. The results are supported by calculating the spin-polarized electronic structure and the electronic charge transfer. Finally, we computed the energy barriers that inhibit the transformation of the linear chain to a delta Mn trimer on both substrates.
报道了对吸附在贵金属表面Au(111)和Cu(111)上的锰三聚体的理论研究。计算是在密度泛函理论和广义梯度近似下，采用第一性原理方法在共线和非共线磁相中进行的。通过考虑一个包含25个原子的表面晶胞对该体系进行建模，以改善三聚体在表面的隔离情况。我们将三聚体评估为线性链状和形成三角形结构。三角形三聚体可以以两种可能的构型吸附，一种是在空的表面三角形位点（Δ）上方，另一种是在六边形结构中以表面原子为中心的三角形上（H）。区别在于锰与表面原子的配位情况。我们研究了反铁磁（AF）、铁磁（FM）和非共线（NC）磁性情况。结果表明，两种金属上能量最低的构型是AF构型，呈等腰三角形形状。相比之下，NC和FM构型采用等边几何形状。对于H构型也观察到了相同的趋势，但它们的键合较弱。通过计算自旋极化电子结构和电荷转移来支持这些结果。最后，我们计算了抑制线性链在两种衬底上转变为δ锰三聚体的能垒。
