arXiv subjects

Prasanjit Samal

Publications and source records attributed to Prasanjit Samal.

At least 37 records · Page 2Linked to original sources

arXiv2024

Spin-Phonon interaction in quasi 2D- Cr$_2Te_3$

Spin-phonon interaction plays an important role in 2D magnetic materials and motivates the development of next-generation spin- and charge-dependent microelectronic devices. Understanding the spin-phonon interaction by tuning the growth parameter of single crystal Cr$_2Te_3$, a robust quasi-2D room temperature magnetic material, is crucial for spintronic devices. The synthesis of single crystal 2D Cr$_2Te_3$ flakes on a Si substrate from co-deposited thin film by plasma annealing techniques is a significant achievement. The temperature dependence and polarization-resolved Raman spectroscopy with support of density functional theory classified lattice symmetry operations were used to identify the phonon modes to investigate the spin/electron-phonon interactions in Cr$_2Te_3$. The mean-field theory model in single crystal Cr$_2Te_3$ is employed to quantify the spin-phonon interaction and correlate with in-plane and out-of-plane magnetic behavior. The observation of a positive correlation between phonon mode frequency and spin-phonon interaction strength in single crystal Cr$_2Te_3$ can be a potential candidate for spintronic applications.

cond-mat.mtrl-sci↗

arXiv2024

Accurate and efficient prediction of the band gaps and optical spectra of chalcopyrite semiconductors from a non-empirical range-separated dielectric-dependent hybrid: Comparison with many-body perturbation theory

The accurate prediction of electronic and optical properties in chalcopyrite semiconductors has been a persistent challenge for density functional theory (DFT) based approaches. Addressing this issue, we demonstrate that very accurate results can be obtained using a non-empirical screened dielectric-dependent hybrid (DDH) functional. This novel approach showcases its impressive capability to accurately determine band gaps, optical bowing parameters, and optical absorption spectra for chalcopyrite systems. What sets the screened DDH functional apart is its adeptness in capturing the many-body physics associated with highly localized $d$ electrons. Notably, the accuracy is comparable to the many-body perturbation based methods (such as $G_0W_0$ or its various approximations for band gaps and Bethe-Salpeter equation (BSE) on the top of the $G_0W_0$ or its various approximations for optical spectra) with less computational cost, ensuring a more accessible application across various research domains. The present results show the predictive power of the screened DDH functional, pointing toward promising applications where computational efficiency and predictive accuracy are crucial considerations. Overall, the screened DDH functional offers a compelling balance between cost-effectiveness and precision, making it a valuable tool for future endeavors in exploring chalcopyrite semiconductors and beyond.

cond-mat.mtrl-sci↗

arXiv2023

Semilocal Meta-GGA Exchange-Correlation Approximation From Adiabatic Connection Formalism: Extent and Limitations

The incorporation of a strong interaction regime within the approximate, semilocal exchange-correlation functionals still remains a very challenging task for density functional theory. One of the promising attempts in this direction is the recently proposed adiabatic connection semilocal correlation (ACSC) approach [Phys. Rev. B 2019, 99, 085117] allowing to construct the correlation energy functionals by interpolation of the high and low-density limits for the given semi-local approximation. The current study extends the ACSC method to the meta-GGA level of theory, providing some new insights. As an example, we construct the correlation energy functional base on the high and low-density limits of the Tao-Perdew-Starverov-Scuseria (TPSS) functional. Arose in this way TPSS-ACSC functional is one electron self-interaction free, accurate for the strictly correlated, and quasi-two-dimensional regimes. Based on simple examples, we show the advantages and disadvantages of ACSC semi-local functionals and provide some new guidelines for future developments in this context.

cond-mat.other↗

arXiv2023

Simple and accurate screening parameters for dielectric-dependent hybrids

A simple effective screening parameter for screened range-separated hybrid is constructed from the compressibility sum rule in the context of linear-response time-dependent Density Functional Theory. When applied to the dielectric-dependent hybrid (DDH), it becomes remarkably accurate for bulk solids compared to those obtained from fitting with the model dielectric function or depending on the valence electron density of materials. The present construction of the screening parameter is simple and realistic. The screening parameter developed in this way is physically appealing and practically useful as it is straightforward to obtain using the average over the unit cell volume of the bulk solid, bypassing high-level calculations of the dielectric function depending on random-phase approximation. Furthermore, we have obtained a very good accuracy for energy band gaps, positions of the occupied d-bands, ionization potentials, optical properties of semiconductors and insulators, and geometries of bulk solids (equilibrium lattice constants and bulk moduli) from the constructed DDH.

cond-mat.mtrl-sci↗

arXiv2023

Strain Induced Enhanced Photocatalytic Activities in Layered Two Dimensional C2N/MoS2 Heterostructure: A Meta-GGA Study

The improved photocatalytic water splitting using 2D materials has technological importance for economically viable renewable energy. The present study focuses on the effect of uniaxial, biaxial, and vertical strain on the energy gap and band edge positions of C2N/MoS2 van der Waals heterostructures through first-principles density functional theory using PBE and SCAN functionals. The calculations establish that SCAN functional provides comparatively much better results as compared to the PBE for the band gap and band alignment study. The heterostructure exhibits a type- II band alignment which is beneficial for the efficient separation of charge carriers. For a good photocatalyst, the band edge positions should straddle the water redox potentials. It is observed that for both compressive and tensile vertical strain, the water redox potential values lie within the valence band maximum (VBM) and conduction band minimum (CBM) of the heterostructure. On the other hand, for uniaxial and biaxial strain, the system can be used as a useful photocatalyst only for larger compressive strain, whereas for tensile strain, the energy gap between VBM and CBM keeps on decreasing and lie within the water oxidation/reduction potential. Our study also establishes that the meta-GGA SCAN functional shows similar results as compared to the computationally expensive hybrid HSE functionals. The present work can be extremely useful for experimentalists to design artificial heterostructure devices for better performance in photocatalytic water splitting.

cond-mat.mtrl-sci↗

arXiv2022

Efficient and improved prediction of the band offsets at semiconductor heterojunctions from meta-GGA density functionals

Accurate theoretical prediction of the band offsets at interfaces of semiconductor heterostructures can often be quite challenging. Although density functional theory has been reasonably successful to carry out such calculations and efficient and accurate semilocal functionals are desirable to reduce the computational cost. In general, the semilocal functionals based on the generalized gradient approximation (GGA) significantly underestimate the bulk band gaps. This, in turn, results in inaccurate estimates of the band offsets at the heterointerfaces. In this paper, we investigate the performance of several advanced meta-GGA functionals in the computational prediction of band offsets at semiconductor heterojunctions. In particular, we investigate the performance of r2SCAN (revised strongly-constrained and appropriately-normed functional), rMGGAC (revised semilocal functional based on cuspless hydrogen model and Pauli kinetic energy density functional), mTASK (modified Aschebrock and Kümmel meta-GGA functional), and LMBJ (local modified Becke-Johnson) exchange-correlation functionals. Our results strongly suggest that these meta-GGA functionals for supercell calculations perform quite well, especially, when compared to computationally more demanding GW calculations. We also present band offsets calculated using ionization potentials and electron affinities, as well as band alignment via the branch point energies. Overall, our study shows that the aforementioned meta-GGA functionals can be used within the DFT framework to estimate the band offsets in semiconductor heterostructures with predictive accuracy.

cond-mat.mtrl-sci↗

arXiv2022

Bandgap of two-dimensional materials: Thorough assessment of modern exchange-correlation functionals

The density functional theory (DFT) approximations that are the most accurate for the calculation of band gap of bulk materials are hybrid functionals like HSE06, the MBJ potential, and the GLLB-SC potential. More recently, generalized gradient approximations (GGA), like HLE16, or meta-GGAs, like (m)TASK, have proven to be also quite accurate for the band gap. Here, the focus is on 2D materials and the goal is to provide a broad overview of the performance of DFT functionals by considering a large test set of 298 2D systems. The present work is an extension of our recent studies [Rauch et al., Phys. Rev. B 101, 245163 (2020) and Patra et al., J. Phys. Chem. C 125, 11206 (2021)]. Due to the lack of experimental results for the band gap of 2D systems, $G_{0}W_{0}$ results were taken as reference. It is shown that the GLLB-SC potential and mTASK functional provide the band gaps that are the closest to $G_{0}W_{0}$. Following closely, the local MBJ potential has a pretty good accuracy that is similar to the accuracy of the more expensive hybrid functional HSE06.

cond-mat.mtrl-sci↗

arXiv2021

Correct and accurate polymorphic energy ordering of transition-metal monoxides obtained from semilocal and onsite-hybrid exchange-correlation approximations

The relative energetic stability of the structural phases of common antiferromagnetic transition-metal oxides (MnO, FeO, CoO, and NiO) within the semilocal and hybrid density functionals are fraught with difficulties. In particular, MnO is known to be the most difficult case for almost all common semilocal and hybrid density approximations. Here, we show that the meta-generalized gradient approximation (meta-GGA) constructed from the cuspless hydrogen model and Pauli kinetic energy density (MGGAC) can lead to the correct ground state of MnO. The relative energy differences of zinc-blende (zb) and rock-salt (rs) structures as computed using MGGAC are found to be in nice agreement with those obtained from high-level correlation methods like the random phase approximation or quantum Monte Carlo techniques. Besides, we have also applied the onsite hybrid functionals (closely related to DFT+U ) based on GGA and meta-GGA functionals, and it is shown that a relatively high amount of Hartree-Fock exchange is necessary to obtain the correct ground-state structure. Our present investigation suggests that the semilocal MGGAC and onsite hybrids, both being computationally cheap, as methods of choice for the calculation of the relative stability of antiferromagnetic transition-metal oxides having potential applications in solid-state physics and structural chemistry.

cond-mat.mtrl-sci↗

arXiv2021

Renormalization group analysis of weakly interacting van der Waals Fermi system

Weak-coupling phenomena of the two-dimensional Hubbard model is gaining momentum as a new interesting research field due to its extraordinarily rich behavior as a function of the carrier density and model parameters. Salmhofer [{\it Commun. Math. Phys}. \textbf{194}, 249 (1998);{\it Phys. Rev. Lett}. {\bf 87}, 187004 (2001)] developed a new renormalization-group method for interacting Fermi systems and Metzner [{\it Phys. Rev. B} {\bf 61}, 7364 (2000);{\it Phys. Rev. Lett}. {\bf 85}, 5162 (2000)] implemented this renormalization group analysis of the two-dimensional Hubbard model. In this work, we demonstrate the spin-wave dependent susceptibility behavior of model graphene-phosphorene van der Waals heterostructure in the framework of renormalization group approach. We implement signlet vertex response function for the weakly interacting van der Waals Fermi system with nearest-neighbor hopping amplitudes. This analytical approach is further correlated with {\it ab initio} simulation results and extended for spin-wave dependent susceptibility behavior with possible experimental protocols. We present the resulting compressibility and phase diagram in the vicinity of half-filling, and also results for the density dependence of the critical energy scale.

cond-mat.mes-hall↗

arXiv2021

Improved electronic structure prediction of chalcopyrite semiconductors from a semilocal density functional based on Pauli kinetic energy enhancement factor

The correct treatment of d electrons is of prime importance in order to predict the electronic properties of the prototype chalcopyrite semiconductors. The effect of d states is linked with the anion displacement parameter u, which in turn influences the bandgap of these systems. Semilocal exchange-correlation functionals which yield good structural properties of semiconductors and insulators often fail to predict reasonable u because of the underestimation of the bandgaps arising from the strong interplay between d electrons. In the present study, we show that the meta-generalized gradient approximation (meta-GGA) obtained from the cuspless hydrogen density (MGGAC) [Phys. Rev. B 100, 155140 (2019)] performs in an improved manner in apprehending the key features of the electronic properties of chalcopyrites, and its bandgaps are comparative to that obtained using state-of-art hybrid methods. Moreover, the present assessment also shows the importance of the Pauli kinetic energy enhancement factor, $α=(τ-τ^W)/τ^{unif}$ in describing the d electrons in chalcopyrites. The present study strongly suggests that the MGGAC functional within semilocal approximations can be a better and preferred choice to study the chalcopyrites and other solid-state systems due to its superior performance and significantly low computational cost.

cond-mat.mtrl-sci↗

arXiv2021

Improving the applicability of the Pauli kinetic energy density based semilocal functional for solids

The Pauli kinetic energy enhancement factor $α=(τ-τ^W)/τ^{unif}$ is an important density ingredient, used to construct many meta-generalized gradient approximations (meta-GGA) exchange-correlation (XC) energy functionals, including the very successful strongly constrained and appropriately normed (SCAN) semilocal functional. Another meta-GGA functional, known as MGGAC [Phys. Rev. B 100, 155140 (2019)], is also proposed in recent time depending only on the $α$ ingredient and based on the generalization of the Becke-Roussel approach with the cuspless hydrogen exchange hole density. The MGGAC functional is proved to be a very useful and competitive meta-GGA semilocal functional for electronic structure properties of solids and molecules. Based on the successful implication of the ingredient $α$, which is also useful to construct the one-electron self-interaction free correlation energy functional, here we propose revised correlation energy for MGGAC exchange functional which is more accurate and robust, especially for the high and low-density limits of the uniform density scaling. The present XC functional, named as revised MGGAC (rMGGAC), shows an impressive improvement for the structural and energetic properties of solids compared to its previous version. Moreover, the assessment of the present constructed functional shows to be quite useful in solid-state physics in terms of addressing several current challenging solid-state problems.

cond-mat.mtrl-sci↗

arXiv2020

A way of resolving the order-of-limit problem of Tao-Mo semilocal functional

It is highlighted recently that the Tao-Mo (TM) [Phys. Rev. Lett. 117, 073001 (2016)] semilocal exchange-correlation energy functional suffers from the order-of-limit problem, which affects the functional performance for phase transition pressures [J. Chem. Phys. 152, 244112 (2020)]. The root of the order-of-limit problem of the TM functional inherent within the interpolation function, which switches between the compact density and the slowly varying density. In this paper, we propose a different switch function that avoids the order-of-limit problem and interpolates correctly between the compact density and the slowly varying fourth-order density correction. By circumventing the order-of-limit problem, the proposed form enhances the applicability of the original TM functional on the diverse nature of the solid-state properties. Our conclusion is ensured by examining the functional in predicting properties related to the general-purpose solids, quantum chemistry, and phase transition pressure. Besides, we reasonably discuss the connection between the order-of-limit problem, phase transition pressure, and band gap of solids.

physics.chem-ph↗

arXiv2020

Efficient yet Accurate Dispersion-Corrected Semilocal Exchange-Correlation Functionals For Non-Covalent Interactions

Due to several attractive features, the meta-generalized-gradient approximations (meta-GGAs) are considered to be the most advanced and potentially accurate semilocal exchange-correlation functionals in the rungs of the Jacob's ladder of Density Functional Theory. So far, several meta-GGA are proposed by fitting to the test sets or/and satisfying as many as known exact constraints. Although the density overlap is treated by modern meta-GGA functionals efficiently, for non-covalent interactions, a long-range dispersion correction is essential. In this work, we assess the benchmark performance of different variants of the Tao-Mo semilocal functional (i.e. TM of Phys. Rev. Lett. 117, 073001 (2016) and revTM of J. Phys. Chem. A 123, 6356 (2019)) with Grimme's D3 correction for the several non-covalent interactions, including dispersion and hydrogen bonded systems. We consider the zero, Becke-Johnson(BJ), and optimized power (OP) damping functions within the D3 method, with both TM and revTM functionals. It is observed that the overall performance of the functionals gradually improved from zero to BJ and to OP damping. However, the constructed "OP" corrected (rev)TM+D3(OP) functionals perform considerably better compared to other well-known dispersion corrected functionals. Based on the accuracy of the proposed functionals, the future applicability of these methods is also discussed.

physics.atm-clus↗

arXiv2019

Accurate water properties from an efficient ab-initio method

Accurate prediction of the water properties from a low-cost ab-initio method still a foremost problem for chemists and physicist. Though density functional approaches starting from semilocal to hybrid functionals are tested, those are not efficiently performed for all the properties together, especially, considering energies, conformal ranking, structural and dynamics of water. Also, the inclusion of the long-range van der Waals (vdW) interaction does not improve the ordering stability of isomer. However, relying on the simple revision of the Tao-Mo (revTM) semilocal meta-generalized gradient approximations, we demonstrate that all properties of the water can be accurately predicted. A consistent improvement over several popular ab-initio methods is achieved, indicating the accuracy of this method for describing hydrogen bonding of water.

cond-mat.mtrl-sci↗

arXiv2018

Improving the performance of Tao-Mo non-empirical density functional with broader applicability in quantum chemistry and material sciences

A revised version of the semilocal exchange-correlation functional [Phys. Rev. Lett. 117, 073001 (2016)] (TM) is proposed by incorporating the modifications to its correlation content obtained from the full high-density second-order gradient expansion as proposed in the case of revised Tao-Perdew-Staroverov-Scuseria (revTPSS) [Phys. Rev. Lett. 103, 026403 (2009)] functional. The present construction improves the performance of TM functional over a wide range of quantum chemical and solid-state properties (thermochemistry and structural). More specifically, the cohesive energies, jellium surface exchange-correlation energies, and real metallic surface energies are improved by preserving the accuracy of the solid-state lattice constants and bulk moduli. The present proposition is not only physically motivated but also enhances the applicability of the TM functional. New physical insights with proper exemplification of the present modification which is presented here can further serve for more realistic non-empirical density functional construction.

cond-mat.mtrl-sci↗

arXiv2018

Assessing the performance of the recent non-empirical semilocal density functionals on describing the lattice constants, bulk moduli and cohesive energies of alkali, alkaline-earth, and transition metals

The bulk properties (lattice constants, bulk moduli, and cohesive energies) of alkali, alkaline-earth, and transition metals are studied within the framework of the recently developed meta-GGA (meta-Generalized Gradient Approximation) semilocal exchange-correlation functionals. To establish the applicability, broadness and accuracy of meta-GGA functionals we also put the results of PBE (Perdew-Burke-Ernzerhof) and PBEsol (PBE reparametrized for solids) functionals. The interesting feature of the present paper is that it measures the accuracy of the recently developed TM (Tao-Mo) and TMTPSS (TM exchange with Tao-Perdew-Staroverov-Scuseria (TPSS) correlation) and SCAN (Strongly Constrained and Appropriately Normed) functionals on describing aforementioned properties. The present systematic investigation shows that the TM is accurate in describing the lattice constants while for cohesive energies and bulk moduli the accuracy is biased towards the PBE and TPSS functionals.

cond-mat.mtrl-sci↗

arXiv2018

Efficient lattice constants and energy band gaps for condensed systems from a meta-GGA level screened range separated hybrid functional

A meta generalized gradient level screened range-separated hybrid functional is developed for solid-state electronic structure theory. Assessment of the present range-separated hybrid functional for solid-state lattice constants and band gaps indicate that the present functional can be used for describing those properties efficiently in meta-GGA level. Specifically, the performance of the present functional for band gap of solids indicates that the present meta-GGA level screened hybrids functional is quite productive beyond the GGA level. The most appealing feature of the present formalism is that a method has been suggested which is based upon an accurate semilocal functional.

cond-mat.mtrl-sci↗

arXiv2018

Performance of Tao-Mo semilocal density functional in projector-augmented-wave method

We assess the performance of Tao-Mo semilocal exchange correlation (TM) functional [J. Tao and Y. Mo, Phys. Rev. Lett. 117, 073001 (2016)] using projector-augmented-wave method with the plane wave basis set in Vienna ab initio simulation package (VASP). The meta-GGA level semilocal functional TM is an all purpose exchange-correlation functional which performs accurately for the wide range of molecular and solid state properties. The exchange functional part of TM is designed from the density matrix expansion (DME) technique together with the slowly varying fourth order gradient expansion. The correlation functional of the corresponding exchange is based on Tao-Perdew-Staroverov-Scuseria (TPSS) functional. We assess the performance of TM for solid state lattice constants, bulk moduli, band gaps, cohesive energies and magnetic moments of solids. It has been established that in plane wave basis the TM functional performs accurately in predicting all the solid state properties in semilocal level.

cond-mat.mtrl-sci↗