Pure spin photocurrent in non-centrosymmetric crystals: bulk spin photovoltaic effect

AbstractSpin current generators are critical components for spintronics-based information processing. In this work, we theoretically and computationally investigate the bulk spin photovoltaic (BSPV) effect for creating DC spin current under light illumination. The only requirement for BSPV is inversion symmetry breaking, thus it applies to a broad range of materials and can be readily integrated with existing semiconductor technologies. The BSPV effect is a cousin of the bulk photovoltaic (BPV) effect, whereby a DC charge current is generated under light. Thanks to the different selection rules on spin and charge currents, a pure spin current can be realized if the system possesses mirror symmetry or inversion-mirror symmetry. The mechanism of BSPV and the role of the electronic relaxation time $$\tau$$ τ are also elucidated. We apply our theory to several distinct materials, including monolayer transition metal dichalcogenides, anti-ferromagnetic bilayer MnBi2Te4, and the surface of topological crystalline insulator cubic SnTe.

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Nanoscale Friction on Transition Metal Dichalcogenides: Role of the Chalcogenide

10.26226/morressier.5f5f8e69aa777f8ba5bd5f80 ◽

2020 ◽

Author(s):

Mohammad R. Vazirisereshk

Keyword(s):

Transition Metal ◽

Transition Metal Dichalcogenides ◽

Nanoscale Friction ◽

Metal Dichalcogenides

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Phonon Coupling and Dielectric Response in 2D Semiconductor

NANO ◽

10.1142/s1793292021501319 ◽

2021 ◽

Author(s):

Arslan Usman ◽

Abdul Sattar ◽

Hamid Latif ◽

Muhammad Imran

Keyword(s):

Transition Metal Dichalcogenides ◽

Coupling Mechanism ◽

Two Dimensional ◽

Electron Hole ◽

Exciton Coupling ◽

Gain Energy ◽

Metal Dichalcogenides ◽

Layered Transition Metal ◽

The Impact

The impact of phonon and their surrounding environment on exciton and its complexes were investigated in monolayer WSe2 semiconductor. Phonon up-conversion has been studied in past for conventional III–V semiconductors, but its role in two-dimensional layered transition metal dichalcogenides has rarely been explored. We investigated the photoluminescence up-conversion mechanism in WSe2 monolayer and found that a lower energy photon gain energy upto 64[Formula: see text]meV to be up-converted to emission photon at room temperature. Moreover, the phonon-exciton coupling mechanism has also been investigated and the role of dielectric screening has been explored to get complete insight of coulomb’s interaction in these electron-hole pairs. Investigations of charge carrier’s lifetime reveal that boron nitride encapsulated monolayer has shorter recombination time as low as 41 ps as compared to a bare monolayer on SiO2 substrate. These results are very promising for realizing spintronics-based application from two-dimensional layered semiconductors.

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The role of electron-phonon interactions on the coherence lifetime of monolayer transition metal dichalcogenides

Solid State Communications ◽

10.1016/j.ssc.2017.08.017 ◽

2017 ◽

Vol 266 ◽

pp. 30-33

Author(s):

C.E. Stevens ◽

P. Dey ◽

J. Paul ◽

Z. Wang ◽

H. Zhang ◽

...

Keyword(s):

Transition Metal ◽

Transition Metal Dichalcogenides ◽

Metal Dichalcogenides

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High responsivity in MoS2 phototransistors based on charge trapping HfO2 dielectrics

Communications Materials ◽

10.1038/s43246-020-00103-0 ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Roda Nur ◽

Takashi Tsuchiya ◽

Kasidit Toprasertpong ◽

Kazuya Terabe ◽

Shinichi Takagi ◽

...

Keyword(s):

Transition Metal Dichalcogenides ◽

Charge Trapping ◽

Dual Function ◽

Light Illumination ◽

Low Light ◽

High Responsivity ◽

Metal Dichalcogenides ◽

High Resolution Images ◽

Weak Light ◽

Light Signals

Abstract2D Transition Metal Dichalcogenides hold a promising potential in future optoelectronic applications due to their high photoresponsivity and tunable band structure for broadband photodetection. In imaging applications, the detection of weak light signals is crucial for creating a better contrast between bright and dark pixels in order to achieve high resolution images. The photogating effect has been previously shown to offer high light sensitivities; however, the key features required to create this as a dominating photoresponse has yet to be discussed. Here, we report high responsivity and high photogain MoS2 phototransistors based on the dual function of HfO2 as a dielectric and charge trapping layer to enhance the photogating effect. As a result, these devices offered a very large responsivity of 1.1 × 106 A W−1, a photogain >109, and a detectivity of 5.6 × 1013 Jones under low light illumination. This work offers a CMOS compatible process and technique to develop highly photosensitive phototransistors for future low-powered imaging applications.

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Strain-induced effects on the electronic properties of 2D materials

Nanomaterials and Nanotechnology ◽

10.1177/1847980420902569 ◽

2020 ◽

Vol 10 ◽

pp. 184798042090256 ◽

Cited By ~ 6

Author(s):

Sara Postorino ◽

Davide Grassano ◽

Marco D’Alessandro ◽

Andrea Pianetti ◽

Olivia Pulci ◽

...

Keyword(s):

Electronic Properties ◽

Density Functional ◽

2D Materials ◽

Transition Metal Dichalcogenides ◽

Many Body ◽

Functional Theory ◽

Metal Dichalcogenides ◽

Extreme Sensitivity ◽

Nonuniform Strain

Thanks to the ultrahigh flexibility of 2D materials and to their extreme sensitivity to applied strain, there is currently a strong interest in studying and understanding how their electronic properties can be modulated by applying a uniform or nonuniform strain. In this work, using density functional theory (DFT) calculations, we discuss how uniform biaxial strain affects the electronic properties, such as ionization potential, electron affinity, electronic gap, and work function, of different classes of 2D materials from X-enes to nitrides and transition metal dichalcogenides. The analysis of the states in terms of atomic orbitals allows to explain the observed trends and to highlight similarities and differences among the various materials. Moreover, the role of many-body effects on the predicted electronic properties is discussed in one of the studied systems. We show that the trends with strain, calculated at the GW level of approximation, are qualitatively similar to the DFT ones solely when there is no change in the character of the valence and conduction states near the gap.

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