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Davoudiniya, M., Yang, B. & Sanyal, B. (2024). Influence of ab initio derived site-dependent hopping parameters on electronic transport in graphene nanoribbons. Physical Chemistry, Chemical Physics - PCCP, 26(3), 1936-1949
Open this publication in new window or tab >>Influence of ab initio derived site-dependent hopping parameters on electronic transport in graphene nanoribbons
2024 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 26, no 3, p. 1936-1949Article in journal (Refereed) Published
Abstract [en]

Graphene Nano Ribbons (GNRs) have been studied extensively due to their potential applications in electrical transport, optical devices, etc. The Tight Binding (TB) model is a common method used to theoretically study the properties of GNRs. However, the hopping parameters of two-dimensional graphene (2DG) are often used as the hopping parameters of the TB model of GNRs, which may lead to inaccuracies in the prediction of GNRs. In this work, we calculated the site-dependent hopping parameters from density functional theory and construction of Wannier orbitals for use in a realistic TB model. It has been found that due to the edge effect, the hopping parameters of edge C atoms are markedly different from the bulk part, which is prominently observed in narrow GNRs. Compared to graphene, the change of hopping parameter of edge C atoms of zigzag GNRs (ZGNRs) and armchair GNRs (AGNRs) is as high as 0.11 and 0.08 eV, respectively. Moreover, we investigated the impact of the calculated site-dependent (SD) hopping parameters on the electronic transport properties of GNRs in the absence and presence of the perpendicular electric field and dilute charged impurities using the Green function approach, Landauer–Büttiker formalism and self-consistent Born approximation. We find an electron–hole asymmetry in the electronic structure and transport properties of ZGNRs with SD hopping parameters. Furthermore, AGNRs with SD hopping energies show a band gap regardless of their width, while AGNRs with 2DG hopping parameters exhibit metallic or semiconductor phases depending on their width. In addition, electric field-induced 4-ZGNR with SD hopping parameters undergoes a metallic to n-doped semiconducting phase transition whereas for 4-ZGNR with 2DG hopping parameters and 8-AGNRs with 2DG or SD hopping parameters, the application of an electric field opens the band gap in both conduction and valence bands simultaneously. Our findings provide evidence for the electron–hole symmetry breaking in ZGNR with SD hopping parameters and make ZGNRs a suitable candidate in valleytronic devices.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2024
National Category
Condensed Matter Physics Theoretical Chemistry
Identifiers
urn:nbn:se:uu:diva-522455 (URN)10.1039/d3cp04080a (DOI)001128066100001 ()38116600 (PubMedID)
Funder
Swedish Research Council, 2022-04309National Academic Infrastructure for Supercomputing in Sweden (NAISS), 2023/5-238UPPMAXSwedish National Infrastructure for Computing (SNIC), 2022/3-30National Supercomputer Centre (NSC), SwedenSwedish Research Council, 2022-06725Swedish Research Council, 2018-05973
Available from: 2024-02-07 Created: 2024-02-07 Last updated: 2024-02-07Bibliographically approved
Das, M., Murari, H., Ghosh, S. & Sanyal, B. (2024). Manipulation of electrochemical properties of MXene electrodes for supercapacitor applications by chemical and magnetic disorder. Nanoscale, 16(3), 1352-1361
Open this publication in new window or tab >>Manipulation of electrochemical properties of MXene electrodes for supercapacitor applications by chemical and magnetic disorder
2024 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 16, no 3, p. 1352-1361Article in journal (Refereed) Published
Abstract [en]

The potential of two-dimensional MXenes as electrodes in supercapacitor applications has been studied extensively. However, the role of chemical and magnetic disorder in their electrochemical parameters, e.g., capacitance, has not been explored yet. In this work, we have systematically addressed this for V2−xMnxCO2 MXene solid solutions with an analysis based upon the results from first-principles electronic structure calculations. We find that the variations in the total capacitance over a voltage window depend on the degree of chemical and magnetic disorder. In the course of our investigation, it was also found that the magnetic structure on the surface can substantially influence the redox charge transfer, an as yet unexplored phenomenon. A significantly large charge transfer and thus a large capacitance can be obtained by manipulating the chemical composition and the magnetic order of the surfaces. These findings can be useful in designing operational supercapacitor electrodes with magnetic constituents.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2024
National Category
Condensed Matter Physics Materials Chemistry Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-522459 (URN)10.1039/d3nr03186a (DOI)001128883400001 ()38131380 (PubMedID)
Funder
Swedish Research Council, 2017-05447Carl Tryggers foundation , CTS 20:378
Available from: 2024-02-07 Created: 2024-02-07 Last updated: 2024-02-07Bibliographically approved
Paul, T., Banerjee, A., Das, G. P. & Sanyal, B. (2024). Optimizing solid electrolytes with 3d transition metal doped Li3YCl6 for Li-ion batteries. Journal of Physics D: Applied Physics, 57(14), Article ID 145503.
Open this publication in new window or tab >>Optimizing solid electrolytes with 3d transition metal doped Li3YCl6 for Li-ion batteries
2024 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 57, no 14, article id 145503Article in journal (Refereed) Published
Abstract [en]

Li3YCl6 is a promising candidate for solid electrolytes (SEs) in all-solid-state Li-ion batteries due to its high ionic conductivity, electrochemical stability, and compatibility with metal-oxide electrodes. The monoclinic and trigonal crystal structures of Li3YCl6 with space groups C2/c and P-3m1 have been studied extensively, while little attention has been given to the trigonal P-3c1 phase (space group no. 165). Additionally, Li-ion diffusion mechanism in 3d transition metal (TM) substituted compounds along with their structural stability are interesting to study. Therefore, we investigate the Li diffusion mechanism in Li3YCl6 and TM substituted Li3YCl6 in the P-3c1 phase using first-principles calculations. We have found that all the substituted compounds are thermodynamically stable at room temperature and show high oxidation stability. Li3Y0.875Co0.125Cl6 exhibits the lowest activation energy (0.11 eV) for Li-ion diffusion and the highest Li-ion mobility (σ = 0.39 mS cm−1 at room temperature), which is strongly anisotropic. We used the Crystal Orbital Hamilton Population method to analyze the bonding characteristics of Li3YCl6 and 3d TM substituted Li3YCl6 and found that the Co–Cl bond is weaker than the Cr–Cl bond. This may explain the lower activation energy observed for Li3Y0.875Co0.125Cl6. Our results provide insights into the substitution effect in Li3YCl6 superionic conductors, which could guide the design and development of high-performance SEs for Li-ion batteries.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2024
Keywords
Li-ion battery, electrolytes, diffusivity, DFT
National Category
Inorganic Chemistry Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-521841 (URN)10.1088/1361-6463/ad1b0a (DOI)001144249800001 ()
Funder
Swedish Research Council, 2018-05973Swedish National Infrastructure for Computing (SNIC), 2022/3-30
Available from: 2024-01-29 Created: 2024-01-29 Last updated: 2024-01-29Bibliographically approved
Ipaves, B., Justo, J. F., Sanyal, B. & Assali, L. V. C. (2024). Tuning the Electronic and Mechanical Properties of Two-Dimensional Diamond through N and B Doping. ACS APPLIED ELECTRONIC MATERIALS, 6(1), 386-393
Open this publication in new window or tab >>Tuning the Electronic and Mechanical Properties of Two-Dimensional Diamond through N and B Doping
2024 (English)In: ACS APPLIED ELECTRONIC MATERIALS, ISSN 2637-6113, Vol. 6, no 1, p. 386-393Article in journal (Refereed) Published
Abstract [en]

This paper examines the structural, thermodynamic, dynamic, elastic, and electronic properties of doped 2D diamond C4X2 (X = B or N) nanosheets in both AA ' A '' and ABC stacking configurations, by first-principles calculations. Those systems consist of three diamond-like graphene sheets with an undoped graphene layer between two 50% doped ones. Our results, based on the analysis of ab initio molecular dynamics simulations, phonon dispersion spectra, and Born's criteria for mechanical stability, revealed that all four structures are stable. Additionally, their standard enthalpy of formation values are similar to that of pristine 2D diamonds, recently synthesized by compressing three graphene layers together. The C4X2 (X = B or N) systems exhibit high elastic constant values and stiffness comparable to that of bulk diamond. The C4N2 nanosheets present wide indirect band gaps that could be advantageous for applications similar to those of the hexagonal boron nitride (h-BN), such as a substrate for high-mobility 2D devices. On the other hand, the C4B2 systems are semiconductors with direct band gaps, in the 1.6-2.0 eV range, and small effective masses, which are favorable characteristics to high carrier mobility and optoelectronics applications.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2024
Keywords
2D diamond, diamane, ultrathin diamond films, functionalization, DFT, first-principles calculations
National Category
Condensed Matter Physics Inorganic Chemistry Computational Mathematics
Identifiers
urn:nbn:se:uu:diva-522920 (URN)10.1021/acsaelm.3c01398 (DOI)001148222400001 ()
Funder
Swedish National Infrastructure for Computing (SNIC)
Available from: 2024-02-13 Created: 2024-02-13 Last updated: 2024-02-13Bibliographically approved
Varjovi, M. J., Ershadrad, S., Sanyal, B. & Tosoni, S. (2024). Two-dimensional MSi2N4 (M = Ge, Sn, and Pb) monolayers: promising new materials for optoelectronic applications. 2D Materials, 11(1), Article ID 015016.
Open this publication in new window or tab >>Two-dimensional MSi2N4 (M = Ge, Sn, and Pb) monolayers: promising new materials for optoelectronic applications
2024 (English)In: 2D Materials, E-ISSN 2053-1583, Vol. 11, no 1, article id 015016Article in journal (Refereed) Published
Abstract [en]

The recent growth of two-dimensional (2D) layered crystals of MoSi2N4 and WSi2N4 has sparked significant interest due to their outstanding properties and potential applications. This development has paved the way for a new and large family of 2D materials with a general formula of MA( 2)Z( 4). In this regard, motivated by this exciting family, we propose two structural phases (1T- and 1H-) of MoSi2N4 (M = Ge, Sn, and Pb) monolayers and investigate their structural, vibrational, mechanical, electronic and optical properties by using first-principles methods. The two phases have similar cohesive energies, while the 1T structures are found to be more energetically favorable than their 1H counterparts. The analysis of phonon spectra and ab initio molecular dynamics simulations indicate that all the suggested monolayers, except for 1H-MoSi2N4, are dynamically and thermally stable even at elevated temperatures. The elastic stability and mechanical properties of the proposed crystals are examined by calculating their elastic constants (C ij ), in-plane stiffness ( Y2D ), Poisson's ratio (nu), and ultimate tensile strain (UTS). Remarkably, the considered systems exhibit prominent mechanical features such as substantial in-plane stiffness and high UTS. The calculated electronic band structures reveal that both the 1T- and 1H-MoSi2N4 nanosheets are wide-band-gap semiconductors and their energy band gaps span from visible to ultraviolet region of the optical spectrum, suitable for high-performance nanoelectronic device applications. Lastly, the analysis of optical properties shows that the designed systems have isotropic optical spectra, and depending on the type of the system, robust absorption of ultraviolet and visible light (particularly in 1H-PbSi2N4 monolayer) is predicted. Our study not only introduces new members to the family of 2D MA(2)Z(4 )crystals but also unveils their intriguing physical properties and suggests them as promising candidates for diverse nanomechanical and optoelectronic applications.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2024
Keywords
first-principles calculations, electronic properties, mechanical properties, optical properties, MA (2) Z (4) monolayers
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-520507 (URN)10.1088/2053-1583/ad0f2b (DOI)001114331800001 ()
Funder
Swedish Research Council, 2018-05973Swedish Research Council, 2022-04309Swedish National Infrastructure for Computing (SNIC), 2022/3-30
Available from: 2024-01-15 Created: 2024-01-15 Last updated: 2024-01-15Bibliographically approved
Amombo Noa, F. M., Cheung, O., Åhlén, M., Ahlberg, E., Nehla, P., Salazar-Alvarez, G., . . . Öhrström, L. R. (2023). A Hexagon Based Mn(II) Rod Metal-Organic Framework – Structure, SF6 Gas Sorption, Magnetism and Electrochemistry. Chemical Communications
Open this publication in new window or tab >>A Hexagon Based Mn(II) Rod Metal-Organic Framework – Structure, SF6 Gas Sorption, Magnetism and Electrochemistry
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2023 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548XArticle in journal (Refereed) Published
Abstract [en]

A manganese(II) metal-organic framework based on the hexatopic hexakis(4-carboxyphenyl)benzene, cpb6-: [Mn3(cpb)(dmf)3], was solvothermally prepared showing a Langmuir area of 438 m2/g, rapid uptake of sulfur hexafluoride (SF6) as well as electrochemical and magnetic properties, while single crystal diffraction reveals an unusual rod-MOF topology.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2023
National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-495489 (URN)10.1039/D2CC06916D (DOI)000924317600001 ()
Available from: 2023-01-29 Created: 2023-01-29 Last updated: 2023-05-22Bibliographically approved
Zhao, B., Ngaloy, R., Ghosh, S., Ershadrad, S., Gupta, R., Ali, K., . . . Dash, S. P. (2023). A Room-Temperature Spin-Valve with van der Waals Ferromagnet Fe5GeTe2/Graphene Heterostructure. Advanced Materials, 35(16), Article ID 2209113.
Open this publication in new window or tab >>A Room-Temperature Spin-Valve with van der Waals Ferromagnet Fe5GeTe2/Graphene Heterostructure
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2023 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 35, no 16, article id 2209113Article in journal (Refereed) Published
Abstract [en]

The discovery of van der Waals (vdW) magnets opened a new paradigm for condensed matter physics and spintronic technologies. However, the operations of active spintronic devices with vdW ferromagnets are limited to cryogenic temperatures, inhibiting their broader practical applications. Here, the robust room-temperature operation of lateral spin-valve devices using the vdW itinerant ferromagnet Fe5GeTe2 in heterostructures with graphene is demonstrated. The room-temperature spintronic properties of Fe5GeTe2 are measured at the interface with graphene with a negative spin polarization. Lateral spin-valve and spin-precession measurements provide unique insights by probing the Fe5GeTe2/graphene interface spintronic properties via spin-dynamics measurements, revealing multidirectional spin polarization. Density functional theory calculations in conjunction with Monte Carlo simulations reveal significantly canted Fe magnetic moments in Fe5GeTe2 along with the presence of negative spin polarization at the Fe5GeTe2/graphene interface. These findings open opportunities for vdW interface design and applications of vdW-magnet-based spintronic devices at ambient temperatures.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2023
Keywords
2D magnets, Fe5GeTe2, graphene, Hanle spin precession, spin-valve, van der Waals heterostructures, van der Waals magnets
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-511082 (URN)10.1002/adma.202209113 (DOI)000945738100001 ()36641649 (PubMedID)
Funder
Vinnova, 2019-00068Swedish Research Council, 2021-04821Knut and Alice Wallenberg FoundationSwedish Research Council, 2022-04309Swedish Research Council, 2021-04658Swedish Research Council, 2018-05973Swedish National Infrastructure for Computing (SNIC), SNIC 2021/3-38
Available from: 2023-09-07 Created: 2023-09-07 Last updated: 2023-09-07Bibliographically approved
Gürbüz, E., Tas, M., Şaşıoğlu, E., Mertig, I., Sanyal, B. & Galanakis, I. (2023). First-principles prediction of energy band gaps in 18-valence electron semiconducting half-Heusler compounds: Exploring the role of exchange and correlation. Journal of Applied Physics, 134(20), Article ID 205703.
Open this publication in new window or tab >>First-principles prediction of energy band gaps in 18-valence electron semiconducting half-Heusler compounds: Exploring the role of exchange and correlation
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2023 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 134, no 20, article id 205703Article in journal (Refereed) Published
Abstract [en]

The choice of exchange functional is a critical factor in determining the energy bandgap of semiconductors. Ab initio calculations using different exchange functionals, including the conventional generalized-gradient approximation (GGA) functionals, meta-GGA functionals, and hybrid functionals, show significant differences in the calculated energy bandgap for semiconducting half-Heusler compounds. These compounds, which have 18 valence electrons per unit cell, are of great interest due to their thermoelectric properties, making them suitable for energy conversion applications. In addition, accounting for electronic correlations using the GW method also affects the calculated energy bandgaps compared to standard GGA calculations. The variations in calculated energy bandgaps are specific to each material when using different functionals. Hence, a detailed investigation of the electronic properties of each compound is necessary to determine the most appropriate functional for an accurate description of the electronic properties. Our results indicate that no general rules can be established and a comparison with experimental results is required to determine the most appropriate functional.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-508507 (URN)10.1063/5.0178165 (DOI)001115007300009 ()
Funder
Swedish Research Council, 2022-04309Swedish Research Council, 2018-05973Swedish National Infrastructure for Computing (SNIC), 2021/3-38
Available from: 2023-08-02 Created: 2023-08-02 Last updated: 2024-02-08Bibliographically approved
Chen, X., Wang, D., Li, L. & Sanyal, B. (2023). Giant spin-splitting and tunable spin-momentum locked transport in room temperature collinear antiferromagnetic semimetallic CrO monolayer. Applied Physics Letters, 123(2), Article ID 022402.
Open this publication in new window or tab >>Giant spin-splitting and tunable spin-momentum locked transport in room temperature collinear antiferromagnetic semimetallic CrO monolayer
2023 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 123, no 2, article id 022402Article in journal (Refereed) Published
Abstract [en]

In this work, we present theoretical predictions of a two-dimensional collinear antiferromagnetic semimetal, CrO, which exhibits a giant spin-split band structure, spin-momentum locked transport properties, and a high Neel temperature. Specifically, CrO features two pairs of spin-polarized anisotropic Weyl points at the Fermi level. By manipulating the position of these Weyl points with strain, we demonstrate that four different antiferromagnetic spintronic states with zero net magnetic moments can be achieved, including semimetals with two spin-polarized transport channels, half-semimetals, semiconductors with two spin-polarized transport channels, and half-semiconductors. The strain-induced semiconducting state also preserves the ultra-high carrier mobility of Weyl points, and the bandgap can be easily tuned. These findings offer a good avenue in spintronics without net magnetic moment or strong spin-orbit coupling and could lead to the development of antiferromagnetic materials for spintronic applications.

Place, publisher, year, edition, pages
AIP Publishing, 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-509253 (URN)10.1063/5.0147450 (DOI)001027294400001 ()
Funder
Swedish Research Council, 2022-04309Swedish Research Council, 12004097Swedish Research Council, SNIC 2022/3-30Swedish National Infrastructure for Computing (SNIC)
Available from: 2023-08-21 Created: 2023-08-21 Last updated: 2023-08-21Bibliographically approved
Sadhukhan, B., Chimata, R., Sanyal, B. & Mookerjee, A. (2023). Magnetization Dynamics in FexCo1-x in Presence of Chemical Disorder. MAGNETOCHEMISTRY, 9(2), Article ID 44.
Open this publication in new window or tab >>Magnetization Dynamics in FexCo1-x in Presence of Chemical Disorder
2023 (English)In: MAGNETOCHEMISTRY, ISSN 2312-7481, Vol. 9, no 2, article id 44Article in journal (Refereed) Published
Abstract [en]

In this paper, we present a theoretical formulation of magnetization dynamics in disordered binary alloys, based on the Kubo linear response theory, interfaced with a seamless combination of three approaches: density functional-based tight-binding linear muffin-tin orbitals, generalized recursion and augmented space formalism. We applied this method to study the magnetization dynamics in chemically disordered FexCo1-x (x = 0.2, 0.5, 0.8) alloys. We found that the magnon energies decreased with an increase in Co concentration. Significant magnon softening was observed in Fe20Co80 at the Brillouin zone boundary. Magnon-electron scattering increased with increasing Co content, which in turn modified the hybridization between the Fe and Co atoms. This reduced the exchange energy between the atoms and softened down the magnon energy. The lowest magnon lifetime was found in Fe50Co50, where disorder was at a maximum. This clearly indicated that the damping of magnon energies in FexCo1-x was governed by hybridization between Fe and Co, whereas the magnon lifetime was controlled by disorder configuration. Our atomistic spin dynamics simulations show reasonable agreement with our theoretical approach in magnon dispersion for different alloy compositions.

Place, publisher, year, edition, pages
MDPIMDPI, 2023
Keywords
chemical disorder, magnetization dynamics, alloy
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-499214 (URN)10.3390/magnetochemistry9020044 (DOI)000940683700001 ()
Available from: 2023-04-19 Created: 2023-04-19 Last updated: 2024-01-15Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-3687-4223

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