Strain-induced phase transition and giant piezoelectricity in monolayer tellurene

We report the transition of a strain-induced centrosymmetric β-phase to a non-centrosymmetric α-phase for monolayer tellurene based on density functional theory calculations. The phase transition is represented by the displacement of the middle-layer Te atoms from the center of the unit cell in the...

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Bibliographic Details
Published in:Nanoscale 2020-01, Vol.12 (1), p.167-172
Main Authors: Cai, Xueru, Ren, Yangyang, Wu, Menghao, Xu, Dongwei, Luo, Xiaobing
Format: Article
Language:English
Subjects:
Beta phase
Bonding strength
Broken symmetry
Critical point
Density functional theory
Electric fields
Electron spin
Ferroelectric materials
Ferroelectricity
Mathematical analysis
Monolayers
Phase transitions
Phonons
Piezoelectricity
Spin-orbit interactions
Strain analysis
Tensile strain
Unit cell
Vibration mode
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Summary:We report the transition of a strain-induced centrosymmetric β-phase to a non-centrosymmetric α-phase for monolayer tellurene based on density functional theory calculations. The phase transition is represented by the displacement of the middle-layer Te atoms from the center of the unit cell in the y -direction. The critical point for the phase transition is found to be at 0.5% biaxial tensile strain. By analyzing the bond variation and the phonon spectra, we attribute the phase transition to the decrease of the bonding strength at the tensile strain and the atom migration corresponding to the phonon vibration mode along the distorted direction. The transition to the α-phase under strain is further confirmed from the calculated electronic band structure where the spin-orbit coupling (SOC) induces a large Rashba splitting due to symmetry breaking, which may enable the control of spin via the electric field. Two-dimensional ferroelectrics can be formed upon transition of the strain-induced β-phase to the α-phase, and a high polarization of about 90 μC cm −2 can be achieved via a tensile strain, giving rise to a giant piezoelectric coefficient that is two orders of magnitude higher than that of the MoS 2 monolayer. Non-centrosymmetric monolayer α-phase tellurene is demonstrated to be a stable phase under a small tensile strain and possesses giant and tunable piezoelectricity.
ISSN:2040-3364
2040-3372
DOI:10.1039/c9nr06507e