Strain-Induced Isostructural and Magnetic Phase Transitions in Monolayer MoN2.
The change of bonding status, typically occurring only in chemical processes, could dramatically alter the material properties. Here, we show that a tunable breaking and forming of a diatomic bond can be achieved through physical means, i.e., by a moderate biaxial strain, in the newly discovered MoN2 two-dimensional (2D) material. On the basis of first-principles calculations, we predict that as the lattice parameter is increased under strain, there exists an isostructural phase transition at which the N-N distance has a sudden drop, corresponding to the transition from a N-N nonbonding state to a N-N single bond state. Remarkably, the bonding change also induces a magnetic phase transition, during which the magnetic moments transfer from the N(2p) sublattice to the Mo(4d) sublattice; meanwhile, the type of magnetic coupling is changed from ferromagnetic to antiferromagnetic. We provide a physical picture for understanding these striking effects. The discovery is not only of great scientific interest in exploring unusual phase transitions in low-dimensional systems, but it also reveals the great potential of the 2D MoN2 material in the nanoscale mechanical, electronic, and spintronic applications.
International Center for New-Structured Materials (ICNSM) and School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China.|State Key Laboratory of Silicon Materials, Zhejiang University , Hangzhou 310027, China.
Yao
Y
Wang
Research Laboratory for Quantum Materials, Singapore University of Technology and Design , Singapore 487372, Singapore.
Shan-Shan
SS
Wang
International Center for New-Structured Materials (ICNSM) and School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China.|State Key Laboratory of Silicon Materials, Zhejiang University , Hangzhou 310027, China.
Yunhao
Y
Lu
International Center for New-Structured Materials (ICNSM) and School of Materials Science and Engineering, Zhejiang University , Hangzhou 310027, China.|State Key Laboratory of Silicon Materials, Zhejiang University , Hangzhou 310027, China.
Jianzhong
J
Jiang
Research Laboratory for Quantum Materials, Singapore University of Technology and Design , Singapore 487372, Singapore.
Shengyuan A
SA
Yang
Isostructural phase transition; first-principles calculations; magnetic phase transition; transition metal dinitrides; two-dimensional materials