Publications by authors named "Saurav Islam"

Altermagnets are a newly identified family of collinear antiferromagnets with a momentum-dependent spin-split band structure of non-relativistic origin, derived from spin-group symmetry-protected crystal structures. Among candidate altermagnets, CrSb is attractive for potential applications because of a large spin-splitting near the Fermi level and a high Néel transition temperature of around 700 K. Molecular beam epitaxy is used to synthesize CrSb (0001) thin films with thicknesses ranging from 10 to 100 nm.

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Bulk-boundary correspondence, a foundational principle underlying the electronic band structure and physical behavior of topological quantum materials, has been rigorously tested in topological systems that involve conserved charge currents. However, it remains unclear whether bulk-boundary correspondence should hold for nonconserved spin currents. We address this unresolved question by using spin-torque ferromagnetic resonance to accurately probe the charge-to-spin conversion efficiency in epitaxial thin films of a canonical topological insulator, BiSb.

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Time-reversal invariance (TRS) and inversion symmetry (IS) are responsible for the topological band structure in Dirac semimetals (DSMs). These symmetries can be broken by applying an external magnetic or electric field, resulting in fundamental changes to the ground state Hamiltonian and a topological phase transition. We probe these changes using universal conductance fluctuations (UCF) in the prototypical DSM, CdAs.

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As quantum technologies develop, a specific class of electrically conducting materials is rapidly gaining interest because they not only form the core quantum-enabled elements in superconducting qubits, semiconductor nanostructures, or sensing devices, but also the peripheral circuitry. The phase coherence of the electronic wave function in these emerging materials will be crucial when incorporated in the quantum architecture. The loss of phase memory, or dephasing, occurs when a quantum system interacts with the fluctuations in the local electromagnetic environment, which manifests in "noise" in the electrical conductivity.

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Graphene, a two-dimensional nanomaterial, has gained immense interest in biosensing applications due to its large surface-to-volume ratio, and excellent electrical properties. Herein, a compact and user-friendly graphene field effect transistor (GraFET) based ultrasensitive biosensor has been developed for detecting Japanese Encephalitis Virus (JEV) and Avian Influenza Virus (AIV). The novel sensing platform comprised of carboxy functionalized graphene on Si/SiO substrate for covalent immobilization of monoclonal antibodies of JEV and AIV.

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Graphene constitutes one of the key elements in many functional van der Waals heterostructures. However, it has negligible optical visibility due to its monolayer nature. Here we study the visibility of graphene in various van der Waals heterostructures and include the effects of the source spectrum, oblique incidence and the spectral sensitivity of the detector to obtain a realistic model.

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Chlorpyrifos is one of the most widely used pesticides that acts on the nervous system by inhibiting acetylcholinesterase. Prolonged use of chlorpyrifos causes severe neurological, autoimmune, and persistent developmental disorders in humans. Therefore, in this study, a highly sensitive and robust biosensor platform was devised by fabricating graphene field effect transistors (graFET) on Si/SiO substrate for the detection of chlorpyrifos in real samples.

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The myriad technological applications of infrared radiation sensors make the search for ultra-sensitive detectors extremely crucial. Materials such as bismuth telluride (Bi2Te3), having a small bulk band gap of 0.17 eV, are ideal infrared detectors.

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Engineering the properties of layered metal dichalcogenides (LMDs) requires stringent control of their morphology. Herein, using a scalable one-step solvothermal technique, we report the synthesis of SnSe2 under two different conditions, leading to the formation of nanoflakes and nanoflowers. The use of oleic acid in the reaction leads to the formation of nanoflowers, and the presence of ethanol in the reaction medium leads to the formation of nanoflakes.

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Human immunodeficiency virus (HIV), which isa worldwide public health issue, is commonly associated with cardiovascular disorders (CVDs) and rheumatoid arthritis (RA). A smart nanosensor was developed for the detection of HIV and its related diseases (CVDs and RA) using graphene-based field-effect transistors (FETs). In this study, amine-functionalized graphene (afG) was conjugated with antibodies [anti-p24 for HIV, anti-cardiac troponin 1 (anti-cTn1) for CVDs, and anti-cyclic citrullinated peptide (anti-CCP) for RA] to detect various biomarkers.

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Slow intrinsic fluctuations of resistance, also known as the flicker noise or 1/f-noise, in the surface transport of strong topological insulators (TIs) is a poorly understood phenomenon. Here, we have systematically explored the 1/f-noise in field-effect transistors (FET) of mechanically exfoliated Bi1.6Sb0.

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