Symmetry-breaking induced large piezoelectricity in Janus tellurene materials

Chen, Yu; Liu, Junyi; Yu, Jiabing; Guo, Yangyang; Sun, Qiang

doi:10.1039/c8cp04669g

Cited by 161 publications

(109 citation statements)

References 45 publications

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“…Many of them have semiconducting behaviour, which has various potential application in electronics, optoelectronics and piezoelectronics [2][3][4][5] . Their electronic structures, heat transport and piezoelectric properties have been widely investigated [6][7][8][9][10][11][12][13][14][15][16] . It has been proved that the strain can effectively tune electronic structures, transport and piezoelectric properties of 2D materials [15][16][17][18][19][20][21][22][23] , which shows great potential for better use in the nanoelectronic, thermoelectric and piezoelectric applications.…”

Section: Introductionmentioning

confidence: 99%

Tuning the electronic structures and transport coefficients of Janus PtSSe monolayer with biaxial strain

Guo

Deng

2019

Journal of Applied Physics

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Due to their great potential in electronics, optoelectronics and piezoelectronics, Janus transition metal dichalcogenide (TMD) monolayers have attracted increasing research interest, the MoSSe of which with sandwiched S-Mo-Se structure has been synthesized experimentally. In this work, the biaxial strain dependence of electronic structures and transport properties of Janus PtSSe monolayer is systematically investigated by using generalized gradient approximation (GGA) plus spin-orbit coupling (SOC). Calculated results show that SOC has a detrimental effect on power factor of PtSSe monolayer, which can be understood by considering SOC effects on energy bands near the Fermi level. With a/a0 from 0.94 to 1.06, the energy band gap firstly increases, and then decreases, which is due to the position change of conduction band minimum (CBM). It is found that compressive strain can increase the strength of conduction bands convergence by changing relative position of conduction band extrema (CBE), which can enhance n-type ZTe values. Calculated results show that compressive strain can also induce the flat valence bands around the Γ point near the Fermi level, which can lead to high Seebeck coefficient due to large effective masses, giving rise to better p-type ZTe values. The calculated elastic constants with a/a0 from 0.94 to 1.06 all satisfy the mechanical stability criteria, which proves that the PtSSe monolayer is mechanically stable in the considered strain range. Our works further enrich studies of Janus TMD monolayers, and can motivate farther experimental works.

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Section: Introductionmentioning

confidence: 99%

Tuning the electronic structures and transport coefficients of Janus PtSSe monolayer with biaxial strain

Guo

Deng

2019

Journal of Applied Physics

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“…This is the same with ones of MoS 2 monolayer, but is different from ones of Janus monolayer MoSSe with additional e 31 /d 31 32 . For 2D materials, only considering the in-plane strain and stress [32][33][34][35][36][37][38][39][40] , the piezoelectric stress and strain tensors by using Voigt notation can be reduced into:…”

Section: Electronic Structure and Valley Hall Effectmentioning

confidence: 99%

A possible way to achieve anomalous valley Hall effect by piezoelectric effect in $\mathrm{GdCl_2}$ monolayer

Guo,

Zhu,

et al. 2021

Preprint

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Ferrovalley materials can achieve manipulation of the valley degree of freedom with intrinsic spontaneous valley polarization introduced by their intrinsic ferromagnetism. A good ferrovalley material should possess perpendicular magnetic anisotropy (PMA), valence band maximum (VBM)/conduction band minimum (CBM) at valley points, strong ferromagnetic (FM) coupling and proper valley splitting. In this work, the monolayer GdCl2 is proposed as a potential candidate material for valleytronic applications by the first-principles calculations. It is proved that monolayer GdCl2 is a FM semiconductor with the easy axis along out of plane direction and strong FM coupling. A spontaneous valley polarization with a valley splitting of 42.3 meV is produced due to its intrinsic ferromagnetism and spin orbital coupling (SOC). Although the VBM of unstrained monolayer GdCl2 is away from valley points, a very small compressive strain (about 1%) can make VBM move to valley points. We propose a possible way to realize anomalous valley Hall effect in monolayer GdCl2 by piezoelectric effect, not an external electric field, namely piezoelectric anomalous valley Hall effect (PAVHE). This phenomenon could be classified as piezo-valleytronics, being similar to piezotronics and piezophototronics. The only independent piezoelectric strain coefficient d11 is -2.708 pm/V, which is comparable to one of classical bulk piezoelectric material α-quartz (d11=2.3 pm/V). The biaxial in-plane strain and electronic correlation effects are considered to confirm the reliability of our results. Finally, the monolayer GdF2 is predicted to be a ferrovalley material with dynamic and mechanical stabilities, PMA, VBM at valley points, strong FM coupling, valley splitting of 47.6 meV, and d11 of 0.584 pm/V. Our works provide a possible way to achieve anomalous valley Hall effect by piezoelectric effect, which may stimulate further experimental works related with valleytronics.

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“…The e elc ijk /d elc ijk is clamped-ion piezoelectric coefficients, while the e ijk /d ijk is relax-ion piezoelectric coefficients as a realistic result. For 2D materials, ε jk =σ ij =0 for i=3 or j=3 2,[6][7][8] . Due to a 6m2 point-group symmetry of InXO (X=Se and Te) monolayers, the piezoelectric stress and strain tensors with Voigt notation can be reduced into:…”

Section: Piezoelectric Propertiesmentioning

confidence: 99%

“…The monolayer MoS 2 with 2H phase is predicted as a typical 2D piezotronic material 2 , and then is proved to possess piezoelectricity experimentally with e 11 =2.9×10 −10 C/m 3,4 . In theory, the piezoelectric properties of many 2D materials have been reported by DFT calculations 2,[5][6][7][8][9][10][11][12][13] , like transition metal dichalchogenides (TMD), Janus TMD, group IIA and IIB metal oxides, group III-V semiconductors, MA 2 Z 4 family, and group-III monochalcogenides.…”

Section: Introductionmentioning

confidence: 99%

Coexistence of intrinsic piezoelectricity and nontrivial band topology in monolayer InXO (X=Se and Te)

Guo

Zhu

et al. 2021

Preprint

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The combination of piezoelectricity with other unique properties (like topological insulating phase and intrinsic ferromagnetism) in two-dimensional (2D) materials is much worthy of intensive study. In this work, the piezoelectric properties of 2D topological insulators InXO (X=Se and Te) from monolayer InX (X=Se and Te) with double-side oxygen functionalization are studied by density functional theory (DFT). The large piezoelectric strain coefficients (e.g. d11=-13.02 pm/V for InSeO and d11=-9.64 pm/V for InTeO) are predicted, which are comparable and even higher than ones of many other familiar 2D materials. Moreover, we propose two strategies to enhance piezoelectric response of monolayer InXO (X=Se and Te). Firstly, the biaxial strain (0.94-1.06) is applied, and the d11 (absolute value) is increased by 53%/56% for monolayer InSeO/InTeO at 1.06 strain, which is due to increased e11 (absolute value) and reduced C11 − C12. In considered strain range, InXO (X=Se and Te) monolayers are always 2D topological insulators, which confirm the coexistence of piezoelectricity and nontrivial band topology. Secondly, a Janus monolayer In2SeTeO2 is designed by replacing the top Se/Te atomic layer in monolayer InSeO/InTeO with Te/Se atoms, which is dynamically and mechanically stable. More excitingly, Janus monolayer In2SeTeO2 is also a 2D topological insulator with sizeable bulk gap up to 0.158 eV, confirming the coexistence of intrinsic piezoelectricity and topological nature. The calculated d11 is -9.9 pm/V, which is in the middle of ones of InSeO and InTeO monolayers. Finally, the carrier mobilities of monolayer InXO (X=Se and Te) are obtained, which shows a rather pronounced anisotropy between electron and hole, and are almost isotropic between armchair and zigzag directions. Our works imply that it is possible to use the piezotronic effect to control the quantum transport process, ultimately leading to novel device applications in monolayer InXO (X=Se and Te), and can stimulate further experimental works.

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Symmetry-breaking induced large piezoelectricity in Janus tellurene materials

Abstract: A 2D Janus tellurene monolayer with symmetry-breaking can exhibit a large in-plane and an additional out-of-plane piezoelectric polarization.

Cited by 161 publications

References 45 publications

Tuning the electronic structures and transport coefficients of Janus PtSSe monolayer with biaxial strain

Tuning the electronic structures and transport coefficients of Janus PtSSe monolayer with biaxial strain

A possible way to achieve anomalous valley Hall effect by piezoelectric effect in $\mathrm{GdCl_2}$ monolayer

Coexistence of intrinsic piezoelectricity and nontrivial band topology in monolayer InXO (X=Se and Te)

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