Atomically Thin 1T-FeCl₂ Grown by Molecular-Beam Epitaxy

Abstract

Two-dimensional (2D) magnetic materials have attracted much attention due to their unique magnetic properties and promising applications in spintronics. Here, we report on the growth of ferrous chloride (FeCl2) films on Au(111) and graphite with atomic thickness by molecular-beam epitaxy (MBE) and the layer-dependent magnetic properties by density functional theory (DFT) calculations. The growth follows a layer-by-layer mode with adjustable thickness from sub-monolayer to a few layers. Four types of moiré superstructures of a single-layer FeCl2 on graphite and two types of atomic vacancies on Au(111) have been identified based on high-resolution scanning tunneling microscopy (STM). It turned out that the single- and few-layer FeCl2 films grown on Au(111) exhibit a 1T structure. The DFT calculations reveal that a single-layer 1T-FeCl2 has a ferromagnetic ground state. The minimum-energy configuration of a bilayer FeCl2 is satisfied for the 1T–1T structure with ferromagnetic layers coupled antiferromagnetically. These results make FeCl2 a promising candidate as ideal electrodes for spintronic devices providing large magnetoresistance.

Valley Polarization in Monolayer Ferromagnetic FeCl: A First‐Principles Study

“…Figure a,b are the top and side views of 2D FeCl, respectively. Different from the experimentally synthesized hexagonal FeCl 2 , [ 40 ] the FeCl belongs to the tetragonal crystal system and shares the same crystal structure with 2D β‐FeSe thin film, which is a well‐known 2D superconductor material. The first BZ and high‐symmetry points are shown in Figure 1c.…”

Ferroic orders in two-dimensional transition/rare-earth metal halides

“…77 The experimental investigations on M X 2 monolayers or few layers are not as plenty as M X 3 , which call for more attentions in near future. Till now, only FeCl 2 and NiI 2 on substrates were reported, [78][79][80] although their magnetism has not been characterized.…”

Theoretical simulation and design of two-dimensional ferromagnetic materials

“…Torun等人 [86] . 最近, 两个不同的课题组分别利用分子束外延 的方法在高定向热解石墨(highly oriented pyrolytic graphite, HOPG)衬底上成功制备出FeCl 2 单层 [91,92] . 此外, 杂化交换泛函的计算结果表明, 也可以将同类结构的 FeI 2 和FeBr 2 单层从其范德华层状块体中剥离出来, 且 它们都具有半金属特性 [6,87,88] .…”