Carrier-induced phase transition in metal dichlorides XCl2 (X: Fe, Co, and Ni)

• Published in: Journal of magnetism and magnetic materials Vol. 517; p. 167386
• Main Author: Prayitno, Teguh Budi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2021; Elsevier BV
• Subjects: Antiferromagnetism; Carrier density; Cobalt; Dichlorides; Ferromagnetism; Ground state; Hole-electron doping; Iron chlorides; Lattice parameters; Magnetic moments; Metal dichlorides; Monolayers; Nickel; Phase transition; Phase transitions; Spin spiral; Unit cell; Hole-electron doping; Metal dichlorides; Spin spiral; Phase transition
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2020.167386

•Spin spiral state is investigated through generalized Bloch theorem.•Ground states are determined by AFM direct exchange and FM superexchange.•Ground state depends sensitively on lattice constant.•Other ground states can be induced by hole−electron doping. We investigated the ground state of monolayer 1T-XCl2 (X: Fe, Co, and Ni) using the generalized Bloch theorem, which can generate ferromagnetic, spiral, and antiferromagnetic states. Each state was represented by a unique spiral vector that arranges the magnetic moment of magnetic atom in the primitive unit cell. We found the ferromagnetic ground state for the FeCl2 and NiCl2 while the spiral ground state appears for the CoCl2. We also showed that the ground state depends sensitively on the lattice constant. When the hole–electron doping was taken into account, we found the phase transition, which involves the ferromagnetic, spiral, and antiferromagnetic states, for all the systems. Since the spin–spin interaction in the monolayer metal dichlorides is influenced by the competition between the direct exchange and the superexchange, we justify that the carrier concentration determines which interaction should dominate.