arXiv subjects

Abdus Salam Sarkar

Publications and source records attributed to Abdus Salam Sarkar.

9 recordsLinked to original sources

arXiv2025

Advancements in Entangled Photon Pairs in 2D Van der Waals Materials for On-chip Quantum Applications

The next generation of technology is rooted in quantum-based advancements. The entangled photon pair sources play a pivotal role in such wide range of advancement in quantum-based applications, including quantum high precision sensors, communication, computing, cryptography and so on. Scalable on-chip quantum photonic devices hold the key potential to drive transformative advancements in the field. This review article highlights recent breakthroughs and advancements in the generation of entangled photon pairs (EPP) in two dimensional (2D) van der Waals (vdW) materials, with a focus on their applicability to quantum technologies and plausible on-chip quantum integrated photonic device technology. The article begins by discussing the fundamental principles of entangled photon pairs generation. It provides a comprehensive review of the origin and generation of entangled photons in emerging layered vdW materials, alongside various optical quantum characterization techniques. The review then explores key physical parameters of the quantum states associated with entangled photon pairs. Additionally, it examines concepts related to the realization of paired photon generation at the quantum limit. The final section focuses on the potential for on-chip integrated quantum device applications. Beyond highlighting recent advancements in quantum-based research, the review also outlines the current limitations and future prospects aimed at advancing the field.

physics.app-ph↗

arXiv2025

Future prospect of anisotropic 2D tin sulfide (SnS) for emerging electronic and quantum device applications

The family of anisotropic two-dimensional (2D) emerging materials is rapidly evolving due to their low crystal symmetry and in-plane structural anisotropy. Among these, 2D tin sulfide (SnS) has gained significant attention because of its distinctive crystalline symmetry and the resulting extraordinary anisotropic physical properties. This perspective explores recent developments in anisotropic 2D SnS. In particular, it highlights advances in isolating high-quality SnS monolayers (1L-SnS) and in applying advanced techniques for anisotropic characterization. The discussion continues with an overview of the anisotropic optical and electronic properties of SnS, followed by recent progress in emerging electronic device applications, including energy conversion & storage, neuromorphic (synaptic) systems, spintronics and quantum technologies. In addition to presenting significant research findings on SnS, this perspective outlines current limitations and discusses emerging opportunities and future prospects for its application in quantum devices.

cond-mat.mes-hall↗

arXiv2024

Magnetic Switching in Monolayer 2D Diluted Magnetic Semiconductors via Spin-to- Spin Conversion

The integration of two-dimensional (2D) van der Waals (vdW) magnets with topological insulators or heavy metals holds great potential for realizing next-generation spintronic memory devices. However, achieving high-efficiency SOT switching of monolayer vdW magnets at room temperature poses a significant challenge, particularly without an external magnetic field. Here, we show field-free, deterministic, and nonvolatile SOT switching of perpendicular magnetization in the monolayer, diluted magnetic semiconductor (DMS), Fe-doped MoS2(Fe:MoS2) at up to 380 K with a current density of $7\times10^4 A cm^{-2}$. The in situ doping of Fe into monolayer MoS2 via chemical vapor deposition and the geometry-induced strain in the crystal break the rotational switching symmetry in Fe:MoS2, promoting field-free SOT switching by generating out-of-plane spins via spin-to-spin conversion. An apparent anomalous Hall effect (AHE) loop shift at a zero in-plane magnetic field verifies the existence of z spins in Fe:MoS2, inducing an antidamping-like torque that facilitates field-free SOT switching. A strong topological Hall effect (THE) was also observed, attributed to the interfacial Dzyaloshinskii-Moriya interaction (DMI), reducing the energy barrier for SOT switching. This field-free SOT application using a 2D ferromagnetic monolayer provides a new pathway for developing highly power-efficient spintronic memory devices.

cond-mat.mes-hall↗

arXiv2024

Anisotropic Third Harmonic Generation in Two-Dimensional Tin Sulfide

The in-plane anisotropic properties of two-dimensional (2D) group IV monochalcogenides provide an additional degree of freedom which can be used in future optoelectronic devices. Here, it is shown that the third harmonic generation (THG) signal produced by ultrathin tin (II) sulfide (SnS) is in-plane anisotropic with respect to the incident linear polarization of the laser field. We fit the experimental polarization-resolved THG (P-THG) measurements with a nonlinear optics model, which accounts for the orthorhombic crystal structure of 2D SnS. We calculate the relative magnitudes of the \{chi}^(3) tensor components by recording and simultaneously fitting both orthogonal components of the P-THG intensity. Furthermore, we introduce a THG anisotropy ratio, whose calculated values compare the total THG intensity when the excitation linear polarization is along the armchair crystallographic direction with the case when it is along the zigzag direction. Our results provide quantitative information on the anisotropic nature of the THG process in SnS, paving the way to a better understanding of anisotropic nonlinear light-matter interactions, and the development of polarization-sensitive nonlinear optical devices.

physics.optics↗

arXiv2021

In-plane anisotropic quantum confinement effect in ultrasmall SnS sheets

Black phosphorus (BP) analogous tin(II) sulfide (SnS) has recently emerged as an attractive building block for electronic devices due to its highly anisotropic response. Two-dimensional (2D) SnS has shown to exhibit in-plane anisotropy in optical and electrical properties. However, the limitations in growing ultrasmall structures of SnS hinder the experimental exploration of anisotropic behavior in low dimension. Here, we present an elegant approach of synthesizing highly crystalline nanometer-sized SnS sheets. Ultrasmall SnS exhibits two distinct valleys along armchair and zig-zag directions due to in-plane structural anisotropy like bulk SnS. We show that in such SnS nanosheet dots, the band gaps corresponding to two valleys are increased due to quantum confinement effect. We particularly observe that SnS quantum dots (QDs) show excitation energy dependent photoluminescence (PL), which originates from the two nondegenerate valleys. Our work may open up an avenue to show the potential of SnS QDs for new functionalities in electronics and optoelectronics.

cond-mat.mtrl-sci↗

arXiv2020

Dispersion behavior of two dimensional monochalcogenides

Solution processable two-dimensional (2D) materials have provided an ideal platform for both fundamental studies and wearable electronic applications. Apart from graphene and 2D dichalcogenides, IVA-VI monochalcogenides (MMCs) has emerged recently as a promising candidate for next generation electronic applications. However, the dispersion behavior, which is crucial for the quality, solubility and stability of MMCs, has been quite unexplored. Here, the exfoliation and the dispersion behavior of Germanium (II) monosulfide (GeS) and Tin (II) monosulfide (SnS) nanosheets has been investigated in a wide range of organic solvents. Nine different organic solvents were examined and analyzed, considering the solvent polarity, surface tension, and Hansen solubility parameters. A significant yield of isolated GeS and SnS flakes, namely ~16.4 and ~23.08 μg/ml in 2-propanol and N-Methyl-2-pyrrolidone respectively were attained. The isolated flakes are few-layers nanosheets with lateral sizes over a few hundreds of nanometers. The MMCs colloids exhibit long-term stability, suggesting the MMCs applicability for scalable solution processable printed electronic device applications.

cond-mat.mtrl-sci↗

arXiv2020

Recent Advances in Two-Dimensional Metal Monochalcogenides

The family of emerging low-symmetry and structural in-plane anisotropic 2D materials have been expanding rapidly in recent years. As an important emerging anisotropic 2D material, the black phosphorene (BP) analog group IVA-VI metal monochalcogenides (MMCs) have been surged recently due to their distinctive crystalline symmetries, exotic in-plane anisotropic electronic and optical response, earth abundant and environmentally friendly characteristics. In this article, we review the recent research advancements in the field of anisotropic 2D MMCs. At first, the unique wavy crystal structures together with the optical and electronic properties of such materials are discussed. The review continues with the various methods adopted for the synthesis of layered MMCs including micromechanical and liquid phase exfoliation as well as physical vapor deposition. The last part of the article focuses on the application of the structural anisotropic response of 2D MMCs in field effect transistors, photovoltaic cells nonlinear optics and valleytronic devices. Besides presenting the significant research in the field of this emerging class of 2D materials, this review also delineates the existing limitations and discusses emerging possibilities and future prospects.

cond-mat.mtrl-sci↗

arXiv2020

Robust B-exciton emission at room temperature in few-layers of MoS2:Ag nanoheterojunctions embedded into a glass matrix

Tailoring the photoluminescence (PL) properties in two-dimensional (2D) molybdenum disulfide (MoS2) crystals using external factors is critical for its use in valleytronic, nanophotonic and optoelectronic applications. Although significant effort has been devoted towards enhancing or manipulating the excitonic emission in MoS2 monolayers, the excitonic emission in few-layers MoS2 has been largely unexplored. Here, we put forward a novel nano-heterojunction system, prepared with a non-lithographic process, to enhance and control such emission. It is based on the incorporation of few-layers MoS2 into a plasmonic silver metaphosphate glass (AgPO3) matrix. It is shown that, apart from the enhancement of the emission of both A and B excitons, the B-excitonic emission dominates the PL intensity. In particular, we observe an almost six-fold enhancement of the B exciton emission, compared to control MoS2 samples. This enhanced PL at room temperature is attributed to an enhanced exciton-plasmon coupling and it is supported by ultrafast time-resolved spectroscopy that reveals plasmon-enhanced electron transfer that takes place in Ag nanoparticles-MoS2 nanoheterojunctions. Our results provide a great avenue to tailor the emission properties of few-layers MoS2, which could find application in emerging valleytronic devices working with B excitons.

physics.app-ph↗

arXiv2019

Strong many-body interactions in ultrathin anisotropic tin (II) monosulfide

Two-dimensional (2D) tin(II) monosulfide (SnS) with strong structural anisotropy has been proven to be a phosphorene analogue. However, difficulty in isolating very thin layer of SnS pose challenges in practical utilization. Here, we prepare ultrathin SnS via liquid phase exfoliation. With transmission electron microscopy, we identify the buckled structure of 2D SnS. We employ temperature dependent Raman spectroscopy to elucidate electron-phonon interactions, which reveals a linear phonon shifts. The active Raman modes of ultrathin SnS exhibit higher sensitivity to temperature than other 2D materials. Moreover, we demonstrate strong light-matter interaction in ultrathin SnS using Z-scan and ultrafast spectroscopy. Rich exciton-exciton and coherent exciton-photon interactions arising from many-particle excited effects in ultrathin SnS eventually enhances the nonlinear optical properties. Our findings highlight the prospects for the synthesis of ultrathin anisotropic SnS towards the betterment of thermoelectric and photonic devices.

physics.optics↗