Ferromagnetic nodal-line metal in monolayer h -InC

Abstract

Based on first-principles calculations, we predict a new two-dimensional ferromagnetic material that exhibits exotic Fermi surface topology. We show that monolayer hexagonal indium carbide (h-InC) is thermodynamically and dynamically stable, and it energetically favors the ferromagnetic ordering of spins. The perfectly planar geometry in two dimensions, together with ferromagnetism, gives rise to a unique opportunity to encounter intriguing electronic properties, captured in the Fermi surface and band topology. We show that multiple nodal lines coexist in momentum space, accompanied by the electron and hole pockets that touch each other linearly at the nodal lines. Inclusion of spin-orbit coupling enriches the magnetic and electronic properties of h-InC. Spin-orbit coupling leads to an easy-plane type magnetocrystalline anisotropy, and the nodal lines can be tuned into topological nodal points, contingent upon the magnetization direction. Symmetry analysis and a tight-binding model are provided to explain the nodal structure of the bands. Our findings suggest h-InC as a new venue for supporting carbon-based magnetism and exotic band topology in two dimensions.

Two-dimensional topological semimetal states in monolayers Cu$_2$Ge, Fe$_2$Ge, and Fe$_2$Sn

“…This invariance of MAE in the x-y plane is likely to be due to the fact that the FM instability is induced by the highly localized Fe d z 2 and d yz orbitals near E F [see Figs. , as well as ∼400 µeV of the previously predicted 2D nodal-line materials InC [27] and MnN [52]. Therefore, Fe 2 Ge and Fe 2 Sn monolayers can be classified as hard magnetic 2D materials, which barely change the spin orientations via externally applied magnetic field.…”

“…Most of the NLS states have so far been experimentally observed in three-dimensional (3D) materials such as PtSn 4 [21], ZrSiS [22], and PbTaSe 2 [23]. However, recent theoretical and experimental studies of such NLS states have been extended to 2D monolayers [24][25][26][27] whose electronic properties can be easily tuned by mechanical strains [28,29]. Based on the combined angle-resolved photoemission spectroscopy measurements and density-functional theory (DFT) calculations, Feng et al [24] reported the presence of Dirac nodal lines (DNLs) in Cu 2 Si monolayer which is composed of a honeycomb Cu lattice and a triangular Si lattice.…”

Two-dimensional topological semimetals*

“…The second type with T S x symmetry (and with broken P T ) also works, since T S x itself is a kind of magnetic symmetry and is compatible with certain antiferromagnetic configuration. So far, magnetic Weyl-line material candidates have been proposed for the first type, e.g., in monolayer MnN [87], CrN [88], AgN [89], CsS [90], CoSe [91], InC [92], and K 2 N [93]. Fig.…”

Applicability of biaxially oriented poly(trimethylene terephthalate) films using bio‐based 1,3‐propanediol in retort pouches

“…The glass transition temperature (T g ) of OPTT film could not be found during the first heating, which is a typical characteristic of an OPTT film with a draw ratio of at least three times. [20][21][22][23] Crystallinity was calculated based on 145.63 J/g for the 100% crystalline PTT. 24 The calculated percent crystallinity of OPTT using DSC was 36.5%.…”