arXiv subjects

Satadeep Bhattacharjee

Publications and source records attributed to Satadeep Bhattacharjee.

At least 55 records · Page 3Linked to original sources

arXiv2022

Computational design of novel MAX phase alloys for potential hydrogen storage media combining first principles and cluster expansion methods

Finding a suitable material for hydrogen storage at ambient atmospheric conditions is challenging for material scientists and chemists. In this work, using a first principles based cluster expansion approach, the hydrogen storage capacity of Ti2AC (A = Al,Ti, Cr, Mn, Fe, Co, Ni, Cu, and Zn) MAX phase and its alloys were studied. We found that hydrogen is energetically stable in Ti-A layers in which the tetrahedral site consisting of one A atom and three Ti atoms is energetically more favorable for hydrogen adsorption than other sites in the Ti-A layer. Ti2CuC has the highest hydrogen adsorption energy than other Ti2AC phases. We find that 83.33% Cu doped Ti2AlxCu1-xC alloy structure is both energetically and dynamically stable and can store 3.66 wt% hydrogen at ambient atmospheric conditions, which is higher than both Ti2AlC and Ti2CuC phase. These findings indicate that the hydrogen capacity of the MAX phase can be significantly improved by doping an appropriate atom species.

cond-mat.mtrl-sci↗

arXiv2022

Can magneto-transport properties provide insight into the functional groups in semiconducting MXenes?

The Hall scattering factor of Sc2CF2, Sc2CO2 and Sc2C(OH)2 is calculated using Rode's iterative approach by solving the Boltzmann transport equation. This is carried out in conjunction with calculations based on density functional theory. The electrical transport in Sc2CF2, Sc2CO2, and Sc2C(OH)2 is modelled by accounting for both elastic (acoustic and piezoelectric) and inelastic (polar optical phonon) scattering. Polar optical phonon (POP) scattering is the most significant mechanism in these MXenes. We observe that there is a window of carrier concentration where Hall factor acts dramatically; Sc2CF2 obtains an incredible high value of 2.49 while Sc2CO2 achieves a very small value of approximately 0.5, and Sc2C(OH)2 achieves the so called ideal value of 1. We propose in this paper that such Hall factor behaviour has significant promise in the field of surface group identification in MXenes, an issue that has long baffled researchers.

cond-mat.mtrl-sci↗

arXiv2022

Anti-site disorder and Berry curvature driven anomalous Hall effect in spin gapless semiconducting Mn2CoAl Heusler compound

Spin gapless semiconductors exhibit a finite band gap for one spin channel and closed gap for other spin channel, emerged as a new state of magnetic materials with a great potential for spintronic applications. The first experimental evidence for the spin gapless semiconducting behavior was observed in an inverse Heusler compound Mn2CoAl. Here, we report a detailed investigation of the crystal structure and anomalous Hall effect in the Mn2CoAl using experimental and theoretical studies. The analysis of the high-resolution synchrotron x-ray diffraction data shows anti-site disorder between Mn and Al atoms within the inverse Heusler structure. The temperature-dependent resistivity shows semiconducting behavior and follows Mooijs criteria for disordered metal. Scaling behavior of the anomalous Hall resistivity suggests that the anomalous Hall effect in the Mn2CoAl is primarily governed by intrinsic mechanism due to the Berry curvature in momentum space. The experimental intrinsic anomalous Hall conductivity (AHC) is found to be 35 S/cm, which is considerably larger than the theoretically predicted value for ordered Mn2CoAl. Our first-principle calculations conclude that the anti-site disorder between Mn and Al atoms enhances the Berry curvature and hence the value of intrinsic AHC, which is in a very well agreement with the experiment.

cond-mat.mtrl-sci↗

arXiv2022

A general rule for predicting the magnetic moment of Cobalt-based Heusler compounds using compressed sensing and density functional theory

We propose a general rule for estimating the magnetic moments of Co$ 2$(cobalt)-based Heusler alloys, especially when doped with late transition metals. We come up with a descriptor that can characterise both pure Co$_2$YZ compounds and the doped ones with the chemical formula Co$_2$Y$_{1-x}$M$_x$Z (M is the dopant) using online data for magnetic moments of Heusler alloys with Co$_2$YZ structure and compressive sensing approach. The newly proposed descriptor not only depends on the number of valence electrons of the compound also it depends on the number of unoccupied d-electrons in the doping site. A comparison of the performance of the proposed descriptor and the Slater-Pauling rule is made. Unlike the Slater-Pauling rule, which is only effective for half-metallic Heusler compounds, our machine-learning approach is more generic since it applies to any Co$_2$YZ Heusler compounds, regardless of whether they are half-metals or not. We use this new rule to estimate the magnetic moments of a few yet-to-be-discovered Heusler compounds and compare the results to density functional theory (DFT) based calculations. Finally, we use DFT and machine learning investigations to prove their stability.

cond-mat.mtrl-sci↗

arXiv2022

A new palladium alloy with near-ideal hydrogen storage performance

Hydrogen-based fuels demand high-density storage that can operate under ambient temperatures. Pd and its alloys are the most investigated metal hydrides for hydrogen fuel cell applications. This study presented an alternative Pd alloy for hydrogen storage that can store and release hydrogen at room temperature. The surface of the most studied Pd (110) was modified with Au and Rh so that the hydrogen adsorption energy was 0.49 eV and the release temperature was 365 K. Both values are quite near to the optimum values for the adsorption energy and release temperature of a hydrogen fuel cell in real-world usage.

cond-mat.mtrl-sci↗

arXiv2022

Surface-oxygen-passivation driven large anomalous Hall conductivity (AHC) in nitride MXenes: Can AHC be a tool to determine functional groups in 2D ferro(i)magnets?

Identifying the existence of specific functional groups in MXenes is a difficult topic that has perplexed researchers for a long time. We show in this paper that in the case of magnetic MXenes, the magneto-transport properties of the material provide an easy solution. One of the fascinating properties that MXenes offer is the realization of intrinsic ferromagnetism which is important for two-dimensional (2D) materials family. The previous reports have only made a few statements on some MXenes citing its usefulness for spintronics related applications. Here, using first-principle calculations we have examined the actual magneto-transport phenomena in MXenes family. We have considered all possible combinations of 3\textit{d} transition metals ($Ti, V, Cr$ and $Mn$) and nitride based functionalized $(O_2, F_2$ and $(OH)_2$) MXenes, $M_2NT_2$. The intrinsic anomalous Hall effect is investigated in $Cr$ and $Mn$ based MXenes as the compounds possess ground state stable ferromagnetic solutions. We demonstrate that intrinsic Anomalous Hall conductivity (AHC) can be used to identify the functional groups in MXenes. Additionally, half-metallic features of these ferromagnetic MXenes make them potential candidates for varieties of applications such as in logic and memory devices, quantum computations, spintronics etc. The maximum anomalous Hall conductivity (AHC) at Fermi energy, $E_F$, is found in case of $Mn_2NO_2$ (470 $S/cm$) which is attributed to the presence of avoided band crossing and larger density of states. Together, when considered all the studied systems, the AHC can be above 2500 $S/cm$ within $E_F \pm $ 0.25 $eV$. Our findings could be useful not only in guiding the experimentalists by considering AHC as a simple tool in determining the functional groups in 2D ferro(i)magnets, also, it could be useful in designing memory device with negligible stray fields.

cond-mat.mtrl-sci↗

arXiv2022

Electrical and magneto transport in 2D semiconducting MXene Ti2CO2

The Hall scattering factor is formulated using Rode's iterative approach to solving the Boltzmann transport equation in such a way that it may be easily computed within the scope of ab-inito calculations. Using this method in conjunction with density functional theory based calculations, we demonstrate that the Hall scattering factor in electron-doped Ti2CO2 varies greatly with temperature and concentration, ranging from 0.2 to around 1.3 for weak magnetic fields. The electrical transport was modelled primarily using three scattering mechanisms: piezoelectric scattering, acoustic scattering, and polar optical phonons. Even though the mobility in this material is primarily limited by acoustic phonons, piezoelectric scattering also plays an important role which was not highlighted earlier.

cond-mat.mtrl-sci↗

arXiv2022

Pressure induced isostructural phase transition in biskyrmion host hexagonal MnNiGa

Magnetic skyrmions are vortex-like spin textures, which can be manipulated by external stress or pressure via magnetoelastic effects. Here, we present the observation of isostructural phase transition in a biskyrmion host hexagonal MnNiGa at a pressure around 4 GPa using pressure-dependent synchrotron x-ray powder diffraction (XRD) data analysis. Our XRD data reveals anisotropic compression behavior with pressure with different compression rates of the a-axis in the basal plane and the c-axis in the prismatic plane. However, the hexagonal symmetry remains unchanged for pressure up to 14 GPa. Fitting of unit cell volume with pressure using a second-order Birch-Murnagan equation of state reveals that the data to fall into two distinct curves for those above and below 4 GPa. The present study contributes to the understanding of crystal structure with the application of hydrostatic pressure in the biskyrmion host MnNiGa, wherein the skyrmion textures can be manipulated by pressure due to their magnetoelastic character.

cond-mat.mtrl-sci↗

arXiv2022

Silicene for flexible electronics

The outstanding properties of graphene have laid the foundation for exploring graphene-like two-dimensional systems, commonly referred to as 2D-Xenes. Amongst them, silicene is a front-runner owing to its compatibility with current silicon fabrication technologies. Recent works on silicene have unveiled its useful electronic and mechanical properties. The rapid miniaturization of silicon devices and the useful electro-mechanical properties of silicene necessitates the exploration for potential applications of silicene flexible electronics in the nano electro-mechanical systems. Using a theoretical model derived from the integration of \textit{ab-initio} density-functional theory and quantum transport theory, we investigate the piezoresistance effect of silicene in the nanoscale regime. Like graphene, we obtain a small value of piezoresistance gauge factor of silicene, which is sinusoidally dependent on the transport angle. The small gauge factor of silicene is attributed to its robust Dirac cone and strain-independent valley degeneracy. Based on the obtained results, we propose to use silicene as an interconnect in flexible electronic devices and a reference piezoresistor in strain sensors. This work will hence pave the way for exploring flexible electronics applications in other 2D-Xene materials.

cond-mat.mes-hall↗

arXiv2022

CrysXPP:An Explainable Property Predictor for Crystalline Materials

We present a deep-learning framework, CrysXPP, to allow rapid prediction of electronic, magnetic and elastic properties of a wide range of materials with reasonable precision. Although our work is consistent with several recent attempts to build deep learning-based property predictors, it overcomes some of their limitations. CrysXPP lowers the need for a large volume of tagged data to train a deep learning model by intelligently designing an autoencoder CrysAE and passing the structural information to the property prediction process. The autoencoder in turn is trained on a huge volume of untagged crystal graphs, the designed loss function helps in capturing all their important structural and chemical information. Moreover, CrysXPP uses only a small amount of tagged data for property prediction, and also trains a feature selector that provides interpretability to the results obtained. We demonstrate that CrysXPP convincingly performs better than all the competing and recent baseline algorithms across seven diverse set of properties. Most notably, when given a small amount of experimental data, CrysXPP is consistently able to outperform conventional DFT. We release the large pretrained model CrysAE so that it could be fine-tuned using small amount of tagged data by the research community on various applications with restricted data source.

cond-mat.mtrl-sci↗

arXiv2022

Atomic disorder and Berry phase driven anomalous Hall effect in Co2FeAl Heusler compound

Co2-based Heusler compounds are the promising materials for the spintronics application due to their high Curie temperature, large spin-polarization, large magnetization density, and exotic transport properties. In the present manuscript, we report the anomalous Hall effect (AHE) in a polycrystalline Co2FeAl Heusler compound using combined experimental and theoretical studies. The Rietveld analysis of high-resolution synchrotron x-ray diffraction data reveals a large degree (~50 %) of antisite disorder between Fe and Al atoms. The analysis of anomalous transport data provides the experimental anomalous Hall conductivity (AHC) about 227 S/cm at 2 K with an intrinsic contribution of 155 S/cm, which has nearly constant variation with temperature. The detailed scaling analysis of anomalous Hall resistivity suggests that the AHE in Co2FeAl is governed by the Berry phase driven intrinsic mechanism. Our theoretical calculations reveal that the disorder present in Co2FeAl compound enhances the Berry curvature induced intrinsic AHC.

cond-mat.mtrl-sci↗

arXiv2021

Identifying the critical surface descriptors responsible for the appearance of negative slopes in the adsorption energy scaling relationships

Adsorption energy scaling relationships have now developed beyond their original form, which was more targeted towards the optimization of catalytic sites and the reduction of computational costs in simulations. The recent surge of interest in the adsorption energy scaling relations is to explore the surfaces beyond the transition metals (TMs) as well as reactions involving complicated molecules. Breakdown of such scaling relationships leads to motivating the discovery of novel catalysts with enhanced capabilities. In this work, we report our extensive study on the linear scaling relation (LSR) between oxygen (O), a group VIA element with elements of neighbouring groups such as: Group IIIA (Boron (B), Aluminum (Al)), IVA (Carbon (C), Silicon (Si)), VA (Nitrogen(N),phosphorus(P)) and VIIA (Florine(F)) on magnetic bimetallic surfaces. We found that the slope is positive for only O versus N and F, remaining of the slopes are negative. The present model is based on multiple surface descriptors, particularly spin-averaged d-band center and the surface's magnetic moment, whereas the original scaling theory (Phys. Rev. Lett. 99, 016105 (2007)) was based on a single adsorbate descriptor: adsorbate valency.

cond-mat.mtrl-sci↗

arXiv2021

Probing Photo-excited Charge Carrier Trapping and Defect Formation in Synergistic Doping of SrTiO3

Strontium titanate (SrTiO3) is widely used as a promising photocatalyst due to its unique band edge alignment with respect to the oxidation and reduction potential corresponding to oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). However, further enhancement of the photocatalytic activity in this material could be envisaged through the effective control of oxygen vacancy states. This could substantially tune the photoexcited charge carrier trapping under the influence of elemental functionalization in SrTiO3, corresponding to the defect formation energy. The charge trapping states in SrTiO3 decrease through the substitutional doping in Ti sites with p-block elements like Aluminium (Al) with respect to the relative oxygen vacancies. With the help of electronic structure calculations based on density functional theory (DFT) formalism, we have explored the synergistic effect of doping with both Al and Iridium (Ir) in SrTiO3 from the perspective of defect formation energy, band edge alignment and the corresponding charge carrier recombination probability to probe the photoexcited charge carrier trapping that primarily governs the photocatalytic water splitting process. We have also systematically investigated the ratio-effect of Ir:Al functionalization on the position of acceptor levels lying between Fermi and conduction band in oxygen deficient SrTiO3, which governs the charge carrier recombination and therefore the corresponding photocatalytic efficiency.

cond-mat.mtrl-sci↗

arXiv2021

MatScIE: An automated tool for the generation of databases of methods and parameters used in the computational materials science literature

The number of published articles in the field of materials science is growing rapidly every year. This comparatively unstructured data source, which contains a large amount of information, has a restriction on its re-usability, as the information needed to carry out further calculations using the data in it must be extracted manually. It is very important to obtain valid and contextually correct information from the online (offline) data, as it can be useful not only to generate inputs for further calculations, but also to incorporate them into a querying framework. Retaining this context as a priority, we have developed an automated tool, MatScIE (Material Scince Information Extractor) that can extract relevant information from material science literature and make a structured database that is much easier to use for material simulations. Specifically, we extract the material details, methods, code, parameters, and structure from the various research articles. Finally, we created a web application where users can upload published articles and view/download the information obtained from this tool and can create their own databases for their personal uses.

cs.CL↗

arXiv2021

Cooperation and competition between magnetism and chemisorption

Chemisorption on ferromagnetic and non-magnetic surfaces is discussed within the Newns-Anderson-Grimley model along with the Stoner model of ferromagnetism. In the case of ferromagnetic surfaces, the adsorption energy is formulated in terms of the change in surface magnetic moments. Using such a formulation, we address the issue of how an adsorbate's binding strength depends on the magnetic moments of the surface and how the adsorption process reduces/enhances the magnetic moments of the surface. Our results indicates a possible adsorption energy scaling relationship in terms surface magnetic moments. In the case of non-magnetic surfaces, we formulate a modified stoner criterion and discuss the condition for the appearance of magnetism due to chemisorption on an otherwise non-magnetic surface.

cond-mat.mtrl-sci↗

arXiv2020

Influence of surface structure and strain on indium segregation in InGaAs: a first-principles investigation

The surface segregation of indium atoms in InGaAs is investigated using first-principles calculations based on density functional theory. Through the calculation of segregation energies for (100), (110), and (111) surfaces of GaAs we analyze the decisive role of surface orientation on indium segregation. Further, our calculations reveal that the variation of segregation energy as a function of applied strain strongly depends on surface reconstruction. Obtained segregation energy trends are discussed in light of atomic bonding probed via integrated crystal orbital Hamilton population. Results presented in this paper are anticipated to guide experimental efforts to achieve control on In segregation by managing As-flux along with the application of strain.

cond-mat.mtrl-sci↗

arXiv2020

Population Analysis with Wannier Orbitals

We formulate Wannier orbital overlap population and Wannier orbital Hamilton population to describe the contribution of different orbitals to electron distribution and their interactions. These methods, which are analogous to the well known crystal orbital overlap population and crystal orbital Hamilton population, provide insight into the distribution of electrons at various atom centres and their bonding nature. We apply this formalism in the context of a plane-wave density functional theory calculation. This method provides a means to connect the non-local plane-wave basis to a localised basis by projecting the wave functions from a plane-wave density functional theory calculation on to localized Wannier orbital basis. The main advantage of this formulation is that the spilling factor is strictly zero for insulators and can systematically be made small for metals. We use our proposed method to study and obtain bonding and electron localization insights in five different materials.

physics.comp-ph↗

arXiv2020

Tuning the lattice thermal conductivity in Bismuth Telluride through Cr-doping

Decreasing thermal conductivity of a thermoelectric material is always a prerequisite for its potential application. Using first-principle calculations, we examine the magnetism induced change in lattice thermal transport in bismuth telluride. The source of magnetic moment, Cr in the doped system, weakly magnetizes the coordinated Te atoms to make the latter's phonon softer than that in the pure compound. Though the transition metal dopants do not participate directly in the heat conduction process, the anharmonicity induced by them favor in reducing the lattice thermal conductivity. Large anharmonicity in $(Bi_{0.67}Cr_{0.33})_2Te_3$ reduces the in-plane room temperature lattice thermal conductivity by $\sim 79\%$. The thermal conductivity, strictly, does not vary monotonically with doping concentration. Even, for any particular doping level, the thermal conductivity is different for different configurations which is related to the internal energy of the system. We found that the internal energy variance of 0.03 $eV$ would reduce the in-plane thermal conductivity of the room temperature lattice by at least 60$\%$ for 50$\%$ doping.

cond-mat.mtrl-sci↗