Abstract
Using ab initio density functional theory and single-orbital Hubbard model calculations via the density matrix renormalization group method, we systematically studied the monolayer VOI2 with a 3d1 electronic configuration. Our phonon calculations indicate that the orthorhombic Pmm2 FE-II phase is the most likely ground state, involving a ferroelectric (FE) distortion along the a axis and V-V dimerization along the b axis. Specifically, the "pseudo Jahn-Teller"effect caused by the coupling between empty V (dxz/yz and d3z2-r2) and O 2p states is proposed as the mechanism that stabilizes the FE distortion from the paraelectric phase. Moreover, the half-filled metallic dxy band displays a Peierls instability along the b axis, inducing a V-V dimerization. We also found very short-range antiferromagnetic coupling along the V-V chain due to the formation of nearly decoupled spin singlets in the ground state.
| Original language | English |
|---|---|
| Article number | L121114 |
| Journal | Physical Review B |
| Volume | 103 |
| Issue number | 12 |
| DOIs | |
| State | Published - Mar 22 2021 |
Funding
The work of Y.Z., L.-F.L., A.M., and E.D. is supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division. G.A. was partially supported by the scientific Discovery through Advanced Computing program funded by DOE, Office of Science, Advanced Scientific Computing Research and BES, Division of Materials Sciences and Engineering. All the calculations were carried out at the Advanced Computing Facility of the University of Tennessee, Knoxville.