First-principles study of bulk and two-dimensional structures of the AMnBi family of materials (A=K,Rb,Cs)

Electronic structure and layer-dependent magnetic order of a new high-mobility layered antiferromagnet KMnBi

“…This kind of magnetic square-net has been reported in some intermetal compounds, like CaMnBi2 with P4/nmm space group and SrMnBi2 with I4/nmm space group [40][41][42][43]. Previous neutron diffraction experiments and density functional theory calculations suggested that KMnBi should have a C-type AFM ground state, as schematically illustrated in figure 1(a) [31,33]. The crystal structure of KMnBi respects three symmetry generators, including the inversion symmetry P, fourfold rotation symmetry C 4 and the horizontal glide mirror symmetry G Z .…”

“…This family of compounds were synthesized decades ago but have been rarely investigated [32]. Neutron diffraction experiment confirmed the AFM ground state for the bulk, and such an AFM ordering is expected to be retained down to the 2D limit according to the latest first-principles calculation [31,33]. Furthermore, the tight-binding model calculation suggested that the unique 2D square lattice of AMnBi host topological non-trivial states protected by the nonsymmorphic symmetry [34][35][36].…”

“…The competition in searching for room temperature 2D AFM systems has as well led to the rediscovery of layered manganese-based materials AMnBi (A = K, Rb, Cs), which are narrow-gap semiconductors with the band gap of about 0.3 eV and high carrier mobility exceeding 10 5 cm 2 V −1 s −1 [31]. This family of compounds were synthesized decades ago but have been rarely investigated [32].…”

First-Principles Calculations of Room-Temperature Antiferromagnetism in Crystalline Transition-Metal Borate Nanosheets: Implications for Spintronics Applications

“…However, their low Neél temperature and degradation in ambient conditions hinder their practical applications for spintronics in nanoscale. [7][8][9]13 Two-dimensional (2D) antiferromagnetic materials with roomtemperature T N have also been theoretically proposed, such as semiconducting FeAs-III (T N ∼ 350 K), 14 AMnBi (A = K, Rb, Cs, T N ∼ 300 K), 15 metallic Mn 2 C (T N = 720 K), 16 TMB (TM = Mn, Fe, T N = 300−320 K), 17 and MnX 2 S 4 (X = Al, Ga, T N = 549−702 K). 18 Nevertheless, antiferromagnetic nanosheets with both high T N and ambient stability are still rarely explored.…”

“…Experimentally, antiferromagnetic transition-metal thiophosphates nanosheets have been reported, such as FePS 3 ( T N ∼ 118 K for monolayer), NiPS 3 ( T N ∼ 130 K for bilayer), and MnPS 3 ( T N ∼ 66 K for trilayer), that an important platform to investigate correlated-electron physics, quantum magnonics phenomena, moiré skyrmions, etc. However, their low Néel temperature and degradation in ambient conditions hinder their practical applications for spintronics in nanoscale. − , Two-dimensional (2D) antiferromagnetic materials with room-temperature T N have also been theoretically proposed, such as semiconducting FeAs-III ( T N ∼ 350 K), AMnBi (A = K, Rb, Cs, T N ∼ 300 K), metallic Mn 2 C ( T N = 720 K), TMB (TM = Mn, Fe, T N = 300–320 K), and MnX 2 S 4 (X = Al, Ga, T N = 549–702 K) . Nevertheless, antiferromagnetic nanosheets with both high T N and ambient stability are still rarely explored.…”