Experimental Detection of Topological Electronic State and Large Linear Magnetoresistance in SrSn4 Superconductor Arnab Kumar Pariari, Rajesh O Sharma, Mohammad Balal, Markus Hücker, Tanmoy Das, Sudipta Roy Barman Advanced Functional Materials, 2025 While recent experiments confirm the existence of hundreds of topological electronic materials, only a few exhibit the coexistence of superconductivity (SC) and a topological electronic state. These compounds attract significant attention in forefront research because of the potential for the existence of topological SC, paving the way for future technological advancements. SrSn4 is known for exhibiting unusual SC below the transition temperature (TC) of 4.8 K. Recent theory predicts a topological electronic state in this compound, which is yet to be confirmed by experiments. Systematic and detailed studies of the magnetotransport properties of SrSn4 and its Fermi surface characterizations are also absent. For the first time, a quantum oscillation study reveals a nontrivial 𝝅‐Berry phase, very light effective mass, and high quantum mobility of charge carriers in SrSn4. Magnetotransport experiment unveils large linear transverse magnetoresistance (TMR) of more than 1200% at 5 K and 14 T. Angle‐dependent transport experiments detect anisotropic and fourfold symmetric TMR, with the maximum value (≈2000%) occurring when the angle between the magnetic field and the crystallographic b‐axis is 45°. The results suggest that SrSn4 is the first topological material with SC above the boiling point of helium that displays such high magnetoresistance.
Spin-reorientation driven emergent phases and unconventional magnetotransport in quasi-2D vdW ferromagnet Fe4GeTe2 Riju Pal, Buddhadeb Pal, Suchanda Mondal, Rajesh O. Sharma, Tanmoy Das, Prabhat Mandal, Atindra Nath Pal Npj 2d Materials and Applications, 2024 Non-trivial spin textures driven by strong exchange interaction, magneto-crystalline anisotropy, and electron correlation in a low-dimensional magnetic material often lead to unusual electronic transitions. Through a combination of transport experiments in exfoliated nanoflakes down to 16 layers and first principle calculations, we unravel emergent electronic phases in quasi-2D van der Waals ferromagnet, Fe4GeTe2, possessing ferromagnetic TC ~ 270 K, along with a spin-reorientation transition (TSR ~ 120 K) with the change of magnetic easy axis. Two electronic transitions are identified. The first transition near TSR exhibits a sharp fall in resistivity, followed by a sign change in the ordinary Hall coefficient (R0), together with, maximum negative magnetoresistance (MR) and anomalous Hall conductivity. Another unusual electronic transition, hitherto unknown, is observed near ~ 40–50 K (TQ), where R0 again changes sign and below which, the resistivity shows a quadratic temperature dependence, and MR becomes positive. An analysis of the experimental data further uncovers the role of competing inelastic scattering processes in anomalous magnetotransport behavior. The density-functional theory based first-principle calculations unveil two possible magnetic phases, followed by a low-energy model Hamiltonian which captures the essence of these phases as well as explains the observed magnetotransport behavior. Thus, we demonstrate an interplay between magnetism and band topology and its consequence on electron transport in Fe4GeTe2, important for spintronic applications.
Wire-width and electron-density dependence of the crossover in the peak of the static structure factor from 2kF → 4kF in one-dimensional paramagnetic electron gases Ankush Girdhar, Vinod Ashokan, Rajesh O. Sharma, N. D. Drummond, K. N. Pathak Physical Review B, 2023 We use the variational quantum Monte Carlo (VMC) method to study the wire-width $(b)$ and electron-density $({r}_{\text{s}})$ dependences of the ground-state properties of quasi-one-dimensional paramagnetic electron fluids. The onset of a quasi-Wigner crystal phase is known to depend on electron density and the crossover occurs in the low density regime. We study the effect of wire width on the crossover of the dominant peak in the static structure factor from $k=2{k}_{\text{F}}$ to $k=4{k}_{\text{F}}$. It is found that, for a fixed electron density, in the charge structure factor the crossover from the dominant peak occurring at $2{k}_{\text{F}}$ to $4{k}_{\text{F}}$ occurs as the wire width decreases. Our study suggests that the crossover is due to the interplay of both ${r}_{\text{s}}$ and $b<{r}_{\text{s}}$. The finite wire-width correlation effect is reflected in the peak height of the charge and spin structure factors. We fit the dominant peaks of the charge and spin structure factors assuming fit functions based on our finite wire-width theory and clues from bosonization, resulting in a good fit of the VMC data. The pronounced peaks in the charge and spin structure factors at $4{k}_{\text{F}}$ and $2{k}_{\text{F}}$, respectively, indicate the complete decoupling of the charge and spin degrees of freedom. Furthermore, the wire-width dependence of the electron correlation energy and the Tomonaga-Luttinger parameter ${K}_{\ensuremath{\rho}}$ is found to be significant.
Unconventional Superconductivity at LaVO3/SrTiO3Interfaces Soumyadip Halder, Mona Garg, Nikhlesh Singh Mehta, Anamika Kumari, Rajesh Sharma, Tanmoy Das, Suvankar Chakraverty, Goutam Sheet ACS Applied Electronic Materials, 2022 The conducting interfaces of perovskite oxides are fertile playgrounds of diverse quantum phenomena, and they are potentially important for applications in superconducting nanoelectronic devices. We discovered that the interfaces between the Mott-insulator LaVO3 and the band-insulator SrTiO3 host two-dimensional superconductivity below Tc ≈ 250 mK. Our band structure calculations indicate that for these interfaces, multiple bands (the V and the Ti d bands) cross the Fermi energy where the V d electrons also carry a magnetic moment, thereby raising the possibility of an unconventional order parameter (OP) of the superconducting phase. We have fabricated subsurface soft metallic point-contacts at the LaVO3/SrTiO3 interfaces to probe the OP symmetry spectroscopically through the measurement of Andreev reflection. The spectroscopic features strongly deviate from the expectations within the conventional Bardeen–Cooper–Schriefer framework and support the existence of an unconventional order parameter.
Ground-state properties of electron-electron biwire systems Rajesh O. Sharma, N. D. Drummond, Vinod Ashokan, K. N. Pathak, Klaus Morawetz Physical Review B, 2021 Rajesh O. Sharma, ∗ N. D. Drummond, Vinod Ashokan, K. N. Pathak, and Klaus Morawetz 5 Department of Physics, Panjab University, Chandigarh-160014, India Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom Department of Physics, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar (Punjab) 144011, India Münster University of Applied Sciences, Stegerwaldstrasse 39, 48565 Steinfurt, Germany International Institute of Physics UFRN, Campus Universitário Lagoa nova, 59078-970 Natal, Brazil (Dated: April 2, 2021)
Quantum Monte Carlo Approach for Determining the Activation Barrier of Water Addition to Carbon Monoxide Adsorbed on Pt(111) within 1 kJ/mol Rajesh O. Sharma, Tapio T. Rantala, Philip E. Hoggan Journal of Physical Chemistry C, 2020 Quantum Monte Carlo (QMC) methods offer ab initio calculations of remarkable accuracy for reaction activation barriers (to 1 kJ/mol or 0.01 eV), even at solid surfaces. Chemical reactions generally involve bond dissociation that is poorly described by Hartree–Fock and density functional theory (DFT) methods. However, such processes are often the key to rate-limiting reaction steps at solid surfaces. In this work, a novel QMC methodology is demonstrated as a solution. Carbon monoxide (CO) on platinum reacts with water, first giving the addition products. QMC methods are used here to investigate addition at close-packed Pt(111). The CO is preadsorbed on Pt(111). First, an approaching water molecule is only partially dissociated. At the same time, its oxygen atom binds to CO giving an adsorbed formate moiety (COOH) and Pt–H. This concerted addition is rate-limiting. The QMC activation barrier (in kJ/mol) is 71.0 ± 0.7, and its apparent measured value is 71.4. This showcases QMC as a method to investigate related catalytic systems.
Selective hydrogen production at Pt(111) investigated by Quantum Monte Carlo methods for metal catalysis Rajesh O. Sharma, Tapio T. Rantala, Philip E. Hoggan International Journal of Quantum Chemistry, 2020 This rapid communication gives the salient points and results of the theoretical investigation of a chemical reaction for efficient selective hydrogen production. The clean fuel produced is a sustainable energy source. Accurate methods based on quantum theory are used because the changing electronic structure is a probe that monitors reactions. The reaction between water and carbon monoxide is used industrially with metal catalysts, usually platinum. There is a considerable economic and environmental challenge underpinning this fundamental investigation where bond dissociation plays an essential role. A bond dissociation process is often the limiting step of reaction rates for industrial catalysis. Most mainstream quantum approaches fail to a greater or lesser degree in the description of this process. The present work advocates a promising alternative: the initial analysis of statistical data generated by the Quantum Monte Carlo (QMC) method demonstrated very stringent statistical accuracy for essential information on hydrogen production via the water‐gas shift reaction with platinum catalyst. The transition state structure is obtained from QMC force constants and illustrated here. It corresponds to water OH‐stretch concerted with Pt‐H bond formation, whilst the OH oxygen atom begins to interact with the CO carbon. The present QMC evaluation of the corresponding activation barrier is low: 17.0 ± 0.2 kcal/mol. It is close to the experimental apparent activation energy of 17.05 kcal/mol. This method is applicable to a wide range of similar systems.
The dielectric response and electronic properties of GaS monolayer: A first-principles study Bhagwati Prasad Bahuguna, L. K. Saini, Rajesh O. Sharma Aip Conference Proceedings, 2018 In the present work, we study the electronic structure and optical properties of gallium-sulphide (GaS) monolayer using density functional theory. It is found that GaS monolayer is an indirect bandgap semiconductor with bandgap of 2.58 eV. Optical parameters such as real and imaginary part of dielectric functions, extinction coefficient, refractive index, absorption spectrum, reflectivity, energy loss spectra and optical conductivity of GaS monolayer are calculated within random phase approximation which includes the local field effects at Hartree level. The calculated electronic and optical results suggest that GaS monolayer can have potential applications in nanoelectronic and nanophotonic device.
A variational Monte Carlo study of different spin configurations of electron-hole bilayer Rajesh O. Sharma, L. K. Saini, Bhagwati Prasad Bahuguna Aip Conference Proceedings, 2018 We report quantum Monte Carlo results for mass-asymmetric electron-hole bilayer (EHBL) system with different-different spin configurations. Particularly, we apply a variational Monte Carlo method to estimate the ground-state energy, condensate fraction and pair-correlations function at fixed density rs = 5 and interlayer distance d = 1 a.u. We find that spin-configuration of EHBL system, which consists of only up-electrons in one layer and down-holes in other i.e. ferromagnetic arrangement within layers and anti-ferromagnetic across the layers, is more stable than the other spin-configurations considered in this study.
CELF1 is a non-canonical eIF4E binding protein that promotes translation of epithelial-mesenchymal transition effector mRNAs A Chaudhury, N Kongchan, SA Massey, R Sharma, R Pal, N Zhao, P Tsoi, ... Nucleic acids research 54 (5), gkag123 , 2026 2026 Citations: 1
Coherent magnetic excitations in a topological Kondo semimetal X Zheng, DT Adroja, H Kadowaki, R Sharma, T Das, S Ohira-Kawamura, ... arXiv preprint arXiv:2603.02747 , 2026 2026
Coexistence of Rashba and Ising Spin-Singlet Pairings in Two-Dimensional IrTe K Dutta, RO Sharma, S Das, I Dasgupta, T Das, T Saha-Dasgupta arXiv preprint arXiv:2602.16228 , 2026 2026
Phase-space approach to Wannier pairing and Bogoliubov orbitals in square-octagon lattices RO Sharma, T Das Physical Review B 111 (21), 214522 , 2025 2025
Experimental Detection of Topological Electronic State and Large Linear Magnetoresistance in SrSn 4 Superconductor AK Pariari, RO Sharma, M Balal, M Hücker, T Das, SR Barman Advanced Functional Materials 35 (2), 2412515 , 2025 2025 Citations: 4
Spin-reorientation driven emergent phases and unconventional magnetotransport in quasi-2D vdW ferromagnet Fe 4 GeTe 2 R Pal, B Pal, S Mondal, RO Sharma, T Das, P Mandal, AN Pal npj 2D Materials and Applications 8 (1), 30 , 2024 2024 Citations: 25
Wire-width and electron-density dependence of the crossover in the peak of the static structure factor from in one-dimensional paramagnetic electron … A Girdhar, V Ashokan, RO Sharma, ND Drummond, KN Pathak Physical Review B 107 (11), 115414 , 2023 2023 Citations: 5
Wire width and density dependence of the crossover in the peak of the static structure factor from in one-dimensional paramagnetic electron gases A Girdhar, V Ashokan, RO Sharma, ND Drummond, KN Pathak arXiv preprint arXiv:2212.02225 , 2022 2022
Unconventional Superconductivity at LaVO 3 /SrTiO 3 Interfaces S Halder, M Garg, NS Mehta, A Kumari, R Sharma, T Das, S Chakraverty, ... ACS Applied Electronic Materials 4 (12), 5859-5866 , 2022 2022 Citations: 8
Ground-state properties of electron-electron biwire systems RO Sharma, ND Drummond, V Ashokan, KN Pathak, K Morawetz Physical Review B 104 (3), 035149 , 2021 2021 Citations: 10
Quantum Monte Carlo Approach for Determining the Activation Barrier of Water Addition to Carbon Monoxide Adsorbed on Pt (111) within 1 kJ/mol RO Sharma, TT Rantala, PE Hoggan The Journal of Physical Chemistry C 124 (48), 26232-26240 , 2020 2020 Citations: 15
Selective hydrogen production at Pt (111) investigated by Quantum Monte Carlo methods for metal catalysis RO Sharma, TT Rantala, PE Hoggan International Journal of Quantum Chemistry 120 (11), e26198 , 2020 2020 Citations: 8
Selective hydrogen production at platinum surfaces investigated by the Quantum Monte Carlo approach to chemical reactions RO Sharma, T Rantala, PE Hoggan arXiv preprint arXiv:1908.10782 , 2019 2019 Citations: 1
Physisorption energy of H and H2 on clean Pt (111) as a useful surface energy reference in Quantum Monte Carlo calculation RO Sharma, PE Hoggan Advances in quantum chemistry 79, 311-322 , 2019 2019 Citations: 6
The dielectric response and electronic properties of GaS monolayer: A first-principles study BP Bahuguna, LK Saini, RO Sharma AIP Conference Proceedings 2006 (1), 030016 , 2018 2018 Citations: 1
Phase diagram of a symmetric electron–hole bilayer system: a variational Monte Carlo study RO Sharma, LK Saini, BP Bahuguna Journal of Physics: Condensed Matter 30 (18), 185404 , 2018 2018 Citations: 5
A variational Monte Carlo study of different spin configurations of electron-hole bilayer RO Sharma, LK Saini, BP Bahuguna AIP Conference Proceedings 1953 (1) , 2018 2018
Strain and electric field induced metallization in the GaX (X= N, P, As & Sb) monolayer BP Bahuguna, LK Saini, RO Sharma, B Tiwari Physica E: Low-dimensional Systems and Nanostructures 99, 236-243 , 2018 2018 Citations: 42
Electric field effects on the optical properties of buckled GaAs monolayer BP Bahuguna, LK Saini, RO Sharma AIP Conference Proceedings 1942 (1), 090007 , 2018 2018
Hybrid functional calculations of electronic and thermoelectric properties of GaS, GaSe, and GaTe monolayers BP Bahuguna, LK Saini, RO Sharma, B Tiwari Physical Chemistry Chemical Physics 20 (45), 28575-28582 , 2018 2018 Citations: 112
MOST CITED SCHOLAR PUBLICATIONS
Hybrid functional calculations of electronic and thermoelectric properties of GaS, GaSe, and GaTe monolayers BP Bahuguna, LK Saini, RO Sharma, B Tiwari Physical Chemistry Chemical Physics 20 (45), 28575-28582 , 2018 2018 Citations: 112
Strain and electric field induced metallization in the GaX (X= N, P, As & Sb) monolayer BP Bahuguna, LK Saini, RO Sharma, B Tiwari Physica E: Low-dimensional Systems and Nanostructures 99, 236-243 , 2018 2018 Citations: 42
Spin-reorientation driven emergent phases and unconventional magnetotransport in quasi-2D vdW ferromagnet Fe 4 GeTe 2 R Pal, B Pal, S Mondal, RO Sharma, T Das, P Mandal, AN Pal npj 2D Materials and Applications 8 (1), 30 , 2024 2024 Citations: 25
Electric field induced insulator to metal transition in a buckled GaAs monolayer BP Bahuguna, LK Saini, B Tiwari, RO Sharma RSC advances 6 (58), 52920-52924 , 2016 2016 Citations: 24
Structural, electronic and optical properties of layered GaSe1−xAsx BP Bahuguna, LK Saini, RO Sharma, B Tiwari Computational Materials Science 139, 31 - 38 , 2017 2017 Citations: 21
Quantum Monte Carlo Approach for Determining the Activation Barrier of Water Addition to Carbon Monoxide Adsorbed on Pt (111) within 1 kJ/mol RO Sharma, TT Rantala, PE Hoggan The Journal of Physical Chemistry C 124 (48), 26232-26240 , 2020 2020 Citations: 15
Ground state properties of electron-hole bilayer: Mass-asymmetric effect RO Sharma, LK Saini, BP Bahuguna Physical Review B 94 (20), 205435 , 2016 2016 Citations: 13
Ground-state properties of electron-electron biwire systems RO Sharma, ND Drummond, V Ashokan, KN Pathak, K Morawetz Physical Review B 104 (3), 035149 , 2021 2021 Citations: 10
Unconventional Superconductivity at LaVO 3 /SrTiO 3 Interfaces S Halder, M Garg, NS Mehta, A Kumari, R Sharma, T Das, S Chakraverty, ... ACS Applied Electronic Materials 4 (12), 5859-5866 , 2022 2022 Citations: 8
Selective hydrogen production at Pt (111) investigated by Quantum Monte Carlo methods for metal catalysis RO Sharma, TT Rantala, PE Hoggan International Journal of Quantum Chemistry 120 (11), e26198 , 2020 2020 Citations: 8
Physisorption energy of H and H2 on clean Pt (111) as a useful surface energy reference in Quantum Monte Carlo calculation RO Sharma, PE Hoggan Advances in quantum chemistry 79, 311-322 , 2019 2019 Citations: 6
Wire-width and electron-density dependence of the crossover in the peak of the static structure factor from in one-dimensional paramagnetic electron … A Girdhar, V Ashokan, RO Sharma, ND Drummond, KN Pathak Physical Review B 107 (11), 115414 , 2023 2023 Citations: 5
Phase diagram of a symmetric electron–hole bilayer system: a variational Monte Carlo study RO Sharma, LK Saini, BP Bahuguna Journal of Physics: Condensed Matter 30 (18), 185404 , 2018 2018 Citations: 5
Experimental Detection of Topological Electronic State and Large Linear Magnetoresistance in SrSn 4 Superconductor AK Pariari, RO Sharma, M Balal, M Hücker, T Das, SR Barman Advanced Functional Materials 35 (2), 2412515 , 2025 2025 Citations: 4
The LDA+ U calculation of electronic band structure of GaAs BP Bahuguna, RO Sharma, LK Saini AIP Conference Proceedings 1728 (1), 020601 , 2016 2016 Citations: 4
Quantum Monte Carlo Study of Buckled GaAs Monolayer RO Sharma, LK Saini, BP Bahuguna Macromolecular Symposia 376 (1), 1600206 , 2017 2017 Citations: 3
Electronic and Optical Properties of GaAs Bilayer BP Bahuguna, LK Saini, RO Sharma Macromolecular Symposia 376 (1), 1600208 , 2017 2017 Citations: 3
Diffusion Monte Carlo study of excitons and biexcitons in a mass-asymmetric electron-hole bilayer RO Sharma, LK Saini, BP and Bahuguna Physical Chemistry Chemical Physics , 2017 2017 Citations: 2
CELF1 is a non-canonical eIF4E binding protein that promotes translation of epithelial-mesenchymal transition effector mRNAs A Chaudhury, N Kongchan, SA Massey, R Sharma, R Pal, N Zhao, P Tsoi, ... Nucleic acids research 54 (5), gkag123 , 2026 2026 Citations: 1
Selective hydrogen production at platinum surfaces investigated by the Quantum Monte Carlo approach to chemical reactions RO Sharma, T Rantala, PE Hoggan arXiv preprint arXiv:1908.10782 , 2019 2019 Citations: 1