scholarly journals 1D metallic states at 2D transition metal dichalcogenide semiconductor heterojunctions

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Sridevi Krishnamurthi ◽  
Geert Brocks
Keyword(s):  
Transition Metal ◽  
Density Wave ◽  
Transition Metal Dichalcogenides ◽  
Spin Density Wave ◽  
Electric Polarization ◽  
Transition Metal Dichalcogenide ◽  
First Principles Calculations ◽  
One Dimensional ◽  
Structural Details ◽  
Metal Dichalcogenides

AbstractTwo-dimensional (2D) lateral heterojunctions between different transition metal dichalcogenides (TMDCs) have been realized in recent years. Homogeneous semiconducting TMDC layers are characterized by a topological invariant, their in-plane electric polarization. It suggests the possibility of one-dimensional (1D) metallic states at heterojunctions where the value of the invariant changes. We study such lateral 2D TMDC junctions by means of first-principles calculations and show that 1D metallic states emerge even in cases where the different materials are joined epitaxially. We find that the metallicity does not depend on structural details, but, as the invariant is protected by spatial symmetry only, it can be upset by breaking the symmetry. Indeed, 1D charge- and spin-density wave instabilities appear spontaneously, making 2D TMDC heterojunctions ideal systems for studying 1D systems.

Wrinkle facilitated hydrogen evolution reaction of vacancy-defected transition metal dichalcogenide monolayers

Nanoscale ◽  
2021 ◽  
Author(s):  
Mingjie Pu ◽  
Yufeng Guo ◽  
Wanlin Guo
Keyword(s):  
Hydrogen Production ◽  
Transition Metal ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
First Principles ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
First Principles Calculations ◽  
Catalytic Activities ◽  
Metal Dichalcogenides

Utilizing transition metal dichalcogenides (TMDs) as catalysts in hydrogen evolution reaction (HER) exhibits a promising prospect for hydrogen production. Here by first-principles calculations we reveal that the catalytic activities of...

scholarly journals Unconventional scaling of the superfluid density with the critical temperature in transition metal dichalcogenides

2019 ◽  
Vol 5 (11) ◽  
pp. eaav8465 ◽  
Author(s):  
F. O. von Rohr ◽  
J.-C. Orain ◽  
R. Khasanov ◽  
C. Witteveen ◽  
Z. Shermadini ◽  
...  
Keyword(s):  
Transition Metal ◽  
Muon Spin ◽  
Linear Trend ◽  
Density Wave ◽  
Transition Metal Dichalcogenides ◽  
Superfluid Density ◽  
Muon Spin Rotation ◽  
Transition Metal Dichalcogenide ◽  
Wave State ◽  
Metal Dichalcogenides

We report on muon spin rotation experiments probing the magnetic penetration depth λ(T) in the layered superconductors in 2H-NbSe2 and 4H-NbSe2. The current results, along with our earlier findings on 1T′-MoTe2 (Guguchia et al.), demonstrate that the superfluid density scales linearly with Tc in the three transition metal dichalcogenide superconductors. Upon increasing pressure, we observe a substantial increase of the superfluid density in 2H-NbSe2, which we find to correlate with Tc. The correlation deviates from the abovementioned linear trend. A similar deviation from the Uemura line was also observed in previous pressure studies of optimally doped cuprates. This correlation between the superfluid density and Tc is considered a hallmark feature of unconventional superconductivity. Here, we show that this correlation is an intrinsic property of the superconductivity in transition metal dichalcogenides, whereas the ratio Tc/TF is approximately a factor of 20 lower than the ratio observed in hole-doped cuprates. We, furthermore, find that the values of the superconducting gaps are insensitive to the suppression of the charge density wave state.

scholarly journals Second-harmonic generation enhancement in monolayer transition-metal dichalcogenides by using an epsilon-near-zero substrate

2021 ◽  
Vol 3 (1) ◽  
pp. 272-278
Author(s):  
Pilar G. Vianna ◽  
Aline dos S. Almeida ◽  
Rodrigo M. Gerosa ◽  
Dario A. Bahamon ◽  
Christiano J. S. de Matos
Keyword(s):  
Dielectric Constant ◽  
Transition Metal ◽  
Harmonic Generation ◽  
Nonlinear Effect ◽  
Second Harmonic ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Metal Dichalcogenides ◽  
Epsilon Near Zero

The scheme illustrates a monolayer transition-metal dichalcogenide on an epsilon-near-zero substrate. The substrate near-zero dielectric constant is used as the enhancement mechanism to maximize the SHG nonlinear effect on monolayer 2D materials.

Size-dependent phase stability in transition metal dichalcogenide nanoparticles controlled by metal substrates

Nanoscale ◽  
2021 ◽  
Author(s):  
Albert Bruix ◽  
Jeppe Vang Lauritsen ◽  
Bjork Hammer
Keyword(s):  
Transition Metal ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Phase Stability ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Metal Substrates ◽  
Size Dependent ◽  
Metal Dichalcogenides

Nanomaterials based on MoS2 and related transition metal dichalcogenides are remarkably versatile; MoS2 nanoparticles are proven catalysts for processes such as hydrodesulphurization and the hydrogen evolution reaction, and transition metal...

scholarly journals Exciton g-factors in monolayer and bilayer WSe2 from experiment and theory

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jonathan Förste ◽  
Nikita V. Tepliakov ◽  
Stanislav Yu. Kruchinin ◽  
Jessica Lindlau ◽  
Victor Funk ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Layer Transition ◽  
General Terms ◽  
Indirect Excitons ◽  
Metal Dichalcogenides ◽  
Experimental Findings ◽  
Experimental And Theoretical Studies

Abstract The optical properties of monolayer and bilayer transition metal dichalcogenide semiconductors are governed by excitons in different spin and valley configurations, providing versatile aspects for van der Waals heterostructures and devices. Here, we present experimental and theoretical studies of exciton energy splittings in external magnetic field in neutral and charged WSe2 monolayer and bilayer crystals embedded in a field effect device for active doping control. We develop theoretical methods to calculate the exciton g-factors from first principles for all possible spin-valley configurations of excitons in monolayer and bilayer WSe2 including valley-indirect excitons. Our theoretical and experimental findings shed light on some of the characteristic photoluminescence peaks observed for monolayer and bilayer WSe2. In more general terms, the theoretical aspects of our work provide additional means for the characterization of single and few-layer transition metal dichalcogenides, as well as their heterostructures, in the presence of external magnetic fields.

scholarly journals Exfoliated transition metal dichalcogenide nanosheets for supercapacitor and sodium ion battery applications

2019 ◽  
Vol 6 (8) ◽  
pp. 190437 ◽  
Author(s):  
Santanu Mukherjee ◽  
Jonathan Turnley ◽  
Elisabeth Mansfield ◽  
Jason Holm ◽  
Davi Soares ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Ion ◽  
Coulombic Efficiency ◽  
Transition Metal Dichalcogenides ◽  
Sodium Ion ◽  
Transition Metal Dichalcogenide ◽  
Composite Electrodes ◽  
Metal Dichalcogenides ◽  
Storage Technologies ◽  
Supercapacitor Applications

Growing concerns regarding the safety, flammability and hazards posed by Li-ion systems have led to research on alternative rechargeable metal-ion electrochemical storage technologies. Among the most notable of these are Na-ion supercapacitors and batteries, motivated, in part, by the similar electrochemistry of Li and Na ions. However, sodium ion batteries (SIBs) come with their own set of issues, especially the large size of the Na + ion, its relatively sluggish kinetics and low energy densities. This makes the development of novel materials and appropriate electrode architecture of absolute significance. Transition metal dichalcogenides (TMDs) have attracted a lot of attention in this regard due to their relative ease of exfoliation, diverse morphologies and architectures with superior electronic properties. Here, we study the electrochemical performance of Mo-based two-dimensional (2D) layered TMDs (e.g. MoS 2 , MoSe 2 and MoTe 2 ), exfoliated in a superacid, for battery and supercapacitor applications. The exfoliated TMD flakes were interfaced with reduced graphene oxide (rGO) to be used as composite electrodes. Electron microscopy, elemental mapping and Raman spectra were used to analyse the exfoliated material and confirm the formation of 2D TMD/rGO layer morphology. For supercapacitor applications in aqueous electrolyte, the sulfide-based TMD (MoS 2 ) exhibited the best performance, providing an areal capacitance of 60.25 mF cm −2 . For SIB applications, TMD electrodes exhibited significantly higher charge capacities than the neat rGO electrode. The initial desodiation capacities for the composite electrodes are 468.84 mAh g −1 (1687.82 C g −1 ), 399.10 mAh g −1 (1436.76 C g −1 ) and 387.36 mAh g −1 (1394.49 C g −1 ) for MoS 2 , MoSe 2 and MoTe 2 , respectively. Also, the MoS 2 and MoSe 2 composite electrodes provided a coulombic efficiency of near 100 % after a few initial cycles.

Sign in / Sign up

Export Citation Format

Share Document