Structural Phase Transition of Multilayer VSe<sub>2</sub>

Li, Dian; Wang, Xiong; Kan, Chi Ming; He, Daliang; Li, Zejun; Hao, Qing; Zhao, Hongbo; Wu, Changzheng; Jin, Chuanhong; Cui, Xiaodong

doi:10.1021/acsami.0c04449

Cited by 55 publications

(74 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…But for spin-down channel, VBM is located at C point dominated by V-e 0 g states that strongly hybridized with Se-4p states, and CBM is located at M point dominated by V-e g states, which creates an indirect bandgap of 1.574 eV. The semiconductor behavior of ultrathin 2H-VSe 2 nanoflake (thickness at 30 nm) has been confirmed by experiments [25]. Using standard four-probe configuration, the resistivity of 2H-VSe 2 is measured and shows a nearly exponential decay as temperature increases.…”

Section: Resultsmentioning

confidence: 71%

“…2H-VSe 2 monolayer has not been successfully synthesized experimentally, but its components have been found in the VSe 2 bulk with R polytype for a long time [23], and its stability has been confirmed theoretically [21,24]. After annealing at 650 K, the structural phase transition of multilayer VSe 2 from 1T to 2H has been observed [25].…”

Section: Graphical Abstract Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Magnetic and phonon transport properties of two-dimensional room-temperature ferromagnet VSe2

et al. 2021

View full text Add to dashboard Cite

The room-temperature intrinsic ferromagnetism of monolayer VSe 2 with a van der Waals gap provides an exciting opportunity for both the fundamental studies and future low-dimensional spintronic devices. By applying biaxial strain, the tunable electronic, magnetic, and phonon transport properties of the VSe 2 monolayer are systematically investigated via first-principle calculations. With in-plane easy magnetization axis, the VSe 2 monolayer is always a robust room-temperature ferromagnetic semiconductor in the strain range from -2 to 4%. According to the second-order perturbation theory of spin-orbital coupling, magnetic anisotropy energy is mainly contributed by the interaction between Vd xy orbital and V-d x 2 Ày 2 orbital. The Curie temperature increases significantly with increasing biaxial strain, from 303 to 469 K. In the meantime, room-temperature lattice thermal conductivity is only 0.682 Wm -1 K -1 and exhibits strong strain dependence. The weakened anharmonic three-phonon scattering rate due to the tradeoff between the number and the strength of scattering channel largely compensates for the influence of the reduced phonon group velocity, causing a monotonous increase in the lattice thermal conductivity with the strain changing. Moreover, the lattice thermal conductivity can be reduced further by limiting the size of monolayer under tensile strain, due to the enhanced size dependence of the thermal conductivity.

show abstract

Section: Resultsmentioning

confidence: 71%

Section: Graphical Abstract Introductionmentioning

confidence: 99%

Magnetic and phonon transport properties of two-dimensional room-temperature ferromagnet VSe2

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Each Raman mode showed in good agreement with the previous studies of 1T-VSe2 and Bi2Se3. [43,44] Note that the absence of Raman mode of the semiconducting 2H-VSe2 at 190cm -1 , [45] which can be formed by structural phase transition during the preparation process, implies that the VSe2 used in this study was a pure metallic 1T-phase. The thicknesses of VSe2 at the marked positions (1, 2, 3, and 4) were measured to be 48, 74, 118, and 167 nm on 10 QL Bi2Se3 by atomic force microscopy (AFM), respectively (Fig.…”

Section: Preparation and Characterization Of Vbhsmentioning

confidence: 89%

Ultrafast Interfacial Carrier Dynamics and Persistent Topological Surface States in VSe2/Bi2Se3 Van Der Waals Heterojunctions

Park

Jeon

Chun

et al. 2022

Preprint

View full text Add to dashboard Cite

Vanadium diselenide (VSe2) has recently been highlighted as an efficient 2D electrode owing to its extra-high conductivity, thickness-controllability, and van der Waals epitaxial contact. However, as the electrode, applications of VSe2 to various material systems are still lacking. Here, by employing ultrafast time-resolved spectroscopy, we study VSe2-thickness-dependent interfacial effects in heterostructures with topological insulator Bi2Se3 that is severely affected by contact with conventional 3D electrodes. Our results particularily show unaltered Dirac surface state of Bi2Se3 against forming junctions with VSe2, efficient ultrafast hot electron transfer from VSe2 to Bi2Se3 across the interface, significantly shortened metastable carrier lifetimes in Bi2Se3 due to dipole interactions enabling efficient current flow, and the electronic level shift (~tens meV) of bulk states of Bi2Se3 caused by interfacial interactions, which is ~10 times lower compared to conventional 3D electrodes, implying weak Fermi level pinning. Our observations confirm VSe2 as an ideal electrode for efficient Bi2Se3-based-applications with full utilization of topological insulator characteristics.

show abstract

“…2D VS 2 [15][16][17] , 2D VSe 2 [18][19][20][21] , and VTe 2 [22][23][24][25] were widely studied to seek ideal material platforms for the materials of electrodes, possible roomtemperature 2D ferromagnetism, etc. It was shown that a structural phase transition of multilayer VSe2 from 1T metallic phase to 2H semiconductive phase can be accomplished through annealing at 650 K and the 2H-phase is more thermodynamically favorable than the 1T-phase at the 2D limit 26 . Recently, 2H VSe 2 single crystals were grown and VSe 2 nanoflakes were mechanically exfo-liated onto silicon substrates capped with a oxide layer, and then room-temperature ferromagnetic semiconductor was found in the nanoflakes and attributed to the 2H-phase of VSe 2 in the 2D limit 21 .…”

Section: Introductionmentioning

confidence: 99%

Possible structural and bond reconstruction in 2D ferromagnetic semiconductor VSe2 under uniaxial stress

Yu¹,

Liu²

2022

Preprint

View full text Add to dashboard Cite

Two-dimensional (2D) semiconducting transition metal dichalcogenides have been used to make high-performance electronic, spintronic, and optoelectronic devices. Recently, room-temperature ferromagnetism and semiconducting property were found in 2D VSe2 nanoflakes (mechanically exfoliated onto silicon substrates capped with a oxide layer) and are attributed to the stable 2H-phase of VSe2 in the 2D limit. Here, our first-principles investigation show that a metastable semiconducting H' phase can be formed from the H VSe2 monolayer and some other similar when these 2D H-phase materials are under uniaxial stress or uniaxial strain. For the uniaxial stress (uniaxial strain) scheme, the H' phase will become lower in total energy than the H phase at the transition point. The calculated phonon spectra indicate the dynamical stability of the H' structures of VSe2, VS2, and CrS2, and the path of phase switching between the H and H' VSe2 phases is calculated. For VSe2, the H' phase has stronger ferromagnetism and its Currier temperature can be substantially enhanced by applying uniaxial stress or strain. Spin-resolved electronic structures, energy band edges, and effective carrier masses for both of the H and H' phases can be substantially changed by the applied uniaxial stress or strain, leading to huge effective masses near the band edge of the strained H' phase. Analysis indicated that the largest bond length difference between the H' and H phases can reach -19% for the Se3-Se3' bond, and there is noticeable covalence for the Se3-Se3' bond, which switches the valence of the nearby V atoms, leading to the enhanced ferromagnetism. Therefore, structural and bond reconstruction can be realized by applying uniaxial stress in 2D ferromagnetic H VSe2 and some other similar. These can be useful to seeking more insights and phenomena in such 2D materials for potential applications.

show abstract

Structural Phase Transition of Multilayer VSe₂

Cited by 55 publications

References 30 publications

Magnetic and phonon transport properties of two-dimensional room-temperature ferromagnet VSe2

Magnetic and phonon transport properties of two-dimensional room-temperature ferromagnet VSe2

Ultrafast Interfacial Carrier Dynamics and Persistent Topological Surface States in VSe2/Bi2Se3 Van Der Waals Heterojunctions

Possible structural and bond reconstruction in 2D ferromagnetic semiconductor VSe2 under uniaxial stress

Contact Info

Product

Resources

About

Structural Phase Transition of Multilayer VSe2

Cited by 55 publications

References 30 publications

Magnetic and phonon transport properties of two-dimensional room-temperature ferromagnet VSe2

Magnetic and phonon transport properties of two-dimensional room-temperature ferromagnet VSe2

Ultrafast Interfacial Carrier Dynamics and Persistent Topological Surface States in VSe2/Bi2Se3 Van Der Waals Heterojunctions

Possible structural and bond reconstruction in 2D ferromagnetic semiconductor VSe2 under uniaxial stress

Contact Info

Product

Resources

About

Structural Phase Transition of Multilayer VSe₂