Fig. 5: Structure and magnetism of undistorted and distorted hexagonal FeTe.
From: Phase-controllable growth of ultrathin 2D magnetic FeTe crystals
a Top view of hexagonal FeTe. Lattice constants a and b are marked with the red and green dashed lines, respectively, whereas the purple arc represents angle α between the two lattice vectors. Green dashed arrows show the directions of lattice reshaping, e.g., extended b and enlarged α, in the distorted lattice. b Side view of hexagonal FeTe. Lattice constant c is marked with the pink dashed line while the two pink dashed arrows denote a shrank c in the distorted structure. c, d Atomic differential charge densities of the undistorted and distorted structures in their most stable magnetic orders with an isosurface of 0.006 e/Bohr3. The plotted region is marked in the red dashed rectangle in b. Here, red and green isosurface contours correspond to charge accumulation and reduction after Fe and Te atoms bonding together, respectively. e, f Total density of states of d orbitals for undistorted and distorted hexagonal FeTe, respectively. g Phase diagram of magnetism of the tetragonal and hexagonal phases as a function of temperature. The tetragonal (upper) and hexagonal (lower) phases are separated by the lateral axis of temperature. Blue and red dashed lines represent Tgrowth of the tetragonal (T1) and hexagonal (T2) phases, respectively. Here, the paramagnetic phase is modeled by an Néel AFM configuration for the tetragonal phase above Tc, while it is, most likely, an NM one for the hexagonal phase.
