arXiv subjects

Prince Sharma

Publications and source records attributed to Prince Sharma.

22 records · Page 2Linked to original sources

arXiv2021

Modeling of Magneto-Conductivity of Bismuth Selenide -- A Topological Insulator

We report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of 14Tesla. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR) of around 380 percent at a magnetic field of 14T and a temperature of 5K. The Hikami Larkin Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 Tesla, suggesting that the role of surface driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5 to 200K) and applied magnetic fields (up to 14Tesla).

cond-mat.mtrl-sci↗

arXiv2020

Excited-state dynamics of structurally characterized crystal of SnxSb1-x

The topological behavior of heavy metal alloys opens a vast area for incredible research and future technology. Here, we extend our previous report about the superconducting properties of Sn0.4Sb0.6 along with the compositional variation of Sn and Sb in SnxSb1-x (with (X=0.5 and 0.6)) to study the detailed optical properties. Structural and morphological details of grown crystal are carried from the previous study. Further, the samples are excited by a pump of 2.61 eV with a broad probe of 0.77-1.54 eV in the NIR regime for transient reflectance ultrafast studies (TRUS) measurements. The differential reflectance profile shows an unprecedented negative magnitude, and the average power-dependent analysis of this negative trend has been analyzed. This article not only provides evidence of band filling phenomenon in the samples but also shows that with the variation of average power, there is a definite increase in the excited charge carriers, and thereby enhancing the band filling response. The estimated value of the bandgap between the band filled states and valence state is also determined from these studies. The nonlinear properties and bandgap analysis of the studied topological alloys and similar materials help in the advancement of various nonlinear optical applications.

cond-mat.mtrl-sci↗

arXiv2020

Broad-band spectral analysis of LMXB XTE J1710-281 with Suzaku

This work presents the broad-band time-averaged spectral analysis of neutron star low-mass X-ray binary, XTE J1710-281 by using the Suzaku archival data. The source was in a hard or an intermediate spectral state during this observation. This is the first time that a detailed spectral analysis of the persistent emission spectra of XTE J1710-281 has been done up to 30 keV with improved constraints on its spectral parameters. By simultaneously fitting the XIS (0.6-9.0 keV) and the HXD-PIN (15.0-30.0 keV) data, we have modelled the persistent spectrum of the source with models comprising a soft component from accretion disc and/or neutron star surface/boundary layer and a hard Comptonizing component. The 0.6-30 keV continuum with neutral absorber can be described by a multi-colour disc blackbody with an inner disc temperature of $kT_{\rm disc} = 0.28$ keV, which is significantly Comptonized by the hot electron cloud with electron temperature of $kT_{\rm e} \approx 5$ keV and described by photon index $Γ= 1.86$. A more complex three-component model comprising a multi-colour disc blackbody $\approx 0.30$ keV, single temperature blackbody $\approx 0.65$ keV and Comptonization from the disc, partially absorbed (about 38 per cent) by an ionized absorber (log($ξ$) $\approx$ 4) describes the broad-band spectrum equally well.

astro-ph.HE↗

arXiv2020

Exploration of terahertz from time-resolved ultrafast spectroscopy in single-crystal Bi2Se3 topological insulator

In this article, we reconnoiter the differential reflection signal of a Bi2Se3 single crystal flake, using ultrafast transient absorption spectroscopy in the femtosecond time domain and thereby explore the experimental data in terms of terahertz frequency generated in the sample. An exfoliated flake of a well characterized self-flux grown bulk Bi2Se3 single crystal having rhombohedral structure and layered morphology is used in the present study. The kinetic profile of the same being generated through a reflection signal by a pump laser of 650 nm at an average power of 0.5 mW is studied utilizing time-resolved ultrafast technique. The silhouette as a function of probe delay predicting the capability of the terahertz generation is estimated. Here, two methods FFT (fast Fourier transformation) and FFD (filtering high-frequency component followed by fitting data) are performed to estimate the value of terahertz generated in the system. While comparing the two (FFT & FFD) it is found that a large amount of magnitude difference occurs in the prediction of terahertz frequency. Summarily, we not only report the generation of terahertz in Bi2Se3 flake, also but points out that the exact order of magnitude and the capability of the same depends upon the method of analysis. It is important to extract the vibration signal from the background one so that to find the exact order of magnitude and capability of terahertz generation by any quantum material.

cond-mat.mtrl-sci↗