Clas Persson

• Zhang, Xiaotian; Lin, Changqing; Guo, Xinyi; Xue, Yang; Liang, Xianqing & Zhou, Wenzheng [Vis alle 8 forfattere av denne artikkelen] (2024). Delafossite NaYTe<inf>2</inf> as a transparent conductive material with bipolar conductivity: A first-principles prediction. Journal of Physics and Chemistry of Solids. ISSN 0022-3697. 190. doi: 10.1016/j.jpcs.2024.112002.
• Xue, Yang; Lin, Changqing; Zhong, Jiancheng; Huang, Dan & Persson, Clas (2024). Group-IIIA element doped BaSnS2 as a high efficiency absorber for intermediate band solar cell from a first-principles insight†. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 26(10), s. 8380–8389. doi: 10.1039/d3cp05824g.
• Boström, Mathias; Li, Y.; Brevik, Iver Håkon; Persson, Clas; Carretero-Palacios, S. & Malyi, O. I. (2023). van der Waals induced ice growth on partially melted ice nuclei in mist and fog. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 25, s. 32709–32714. doi: 10.1039/d3cp04157c.
• Ju, Zhiping; Lin, Changqing; Xue, Yang; Huang, Dan & Persson, Clas (2023). First-principles prediction on Ag3SbS4 as a photovoltaic absorber. Journal of Physics and Chemistry of Solids. ISSN 0022-3697. 183. doi: 10.1016/j.jpcs.2023.111655.
• Boström, M.; S., Kuthe; S., Carretero-Palacios; V., Esteso; Li, Y. & Brevik, Iver Håkon [Vis alle 10 forfattere av denne artikkelen] (2023). Understanding ice and water film formation on soil particles by combining density functional theory and Casimir-Lifshitz forces. Physical review B (PRB). ISSN 2469-9950. 108(12). doi: 10.1103/PhysRevB.108.125434.
• Boström, Mathias; Rizwan Khan, M.; Gopidi, H. R.; Brevik, Iver Håkon; Li, Y. & Persson, Clas [Vis alle 7 forfattere av denne artikkelen] (2023). Tuning the Casimir-Lifshitz force with gapped metals. Physical review B (PRB). ISSN 2469-9950. 108(16). doi: 10.1103/PhysRevB.108.165306. Fulltekst i vitenarkiv
• Tan, Xiaoqin; Guo, Xinyi; Xue, Yang; Lin, Changqing; Persson, Clas & Huang, Dan (2023). Band gap tailoring in a low toxicity and low-cost solar cell absorber Cu3SbS4 through Na alloying: A first-principles study. Journal of Crystal Growth. ISSN 0022-0248. 607. doi: 10.1016/j.jcrysgro.2023.127132.
• Fiedler, Johannes; Berland, Kristian; Borchert, James; Corkery, Robert; Eisfeld, Alexander & Gelbwaser-Klimovsky, David [Vis alle 20 forfattere av denne artikkelen] (2022). Perspectives on weak interactions in complex materials at different length scales. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 25, s. 2671–2705. doi: 10.1039/d2cp03349f. Fulltekst i vitenarkiv Vis sammendrag

  Nanocomposite materials consist of nanometer-sized quantum objects such as atoms, molecules, voids or nanoparticles embedded in a host material. These quantum objects can be exploited as a super-structure, which can be designed to create material properties targeted for specific applications. For electromagnetism, such targeted properties include field enhancements around the bandgap of a semiconductor used for solar cells, directional decay in topological insulators, high kinetic inductance in superconducting circuits, and many more. Despite very different application areas, all of these properties are united by the common aim of exploiting collective interaction effects between quantum objects. The literature on the topic spreads over very many different disciplines and scientific communities. In this review, we present a cross-disciplinary overview of different approaches for the creation, analysis and theoretical description of nanocomposites with applications related to electromagnetic properties.

• Huang, Dan; Lin, Changqing; Xue, Yang; Chen, Shiyou; Zhao, Yu-Jun & Persson, Clas (2022). Electronic structure, defect properties, and optimization of the band gap of the earth-abundant and low-toxicity photovoltaic absorber Cu3SbS4. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 24(41), s. 25258–25269. doi: 10.1039/d2cp01941h.
• Larsen, Jes; Sopiha, Kostiantyn; Persson, Clas; Platzer-Björkman, Charlotte & Edoff, Marika (2022). Experimental and Theoretical Study of Stable and Metastable Phases in Sputtered CuInS2. Advanced Science. ISSN 2198-3844. 9(23). doi: 10.1002/advs.202200848. Fulltekst i vitenarkiv
• Li, Yang; Milton, Kimball A.; Brevik, Iver Håkon; Malyi, Oleksandr I.; Thiyam, Priyandarshini & Persson, Clas [Vis alle 8 forfattere av denne artikkelen] (2022). Premelting and formation of ice due to Casimir-Lifshitz interactions: Impact of improved parameterization for materials. Physical review B (PRB). ISSN 2469-9950. 105(1). doi: 10.1103/PhysRevB.105.014203. Fulltekst i vitenarkiv
• Assmann, Nicole; Persson, Clas; Kuznetsov, Andrej & Monakhov, Eduard (2021). Fine structure in electronic transitions attributed to nitrogen donor in silicon carbide. Applied Physics Letters. ISSN 0003-6951. 119(26). doi: 10.1063/5.0074046. Fulltekst i vitenarkiv
• Sopiha, Kostiantyn; Malyi, Oleksandr; Persson, Clas & Wu, Ping (2021). Chemistry of Oxygen Ionosorption on SnO2 Surfaces. ACS Applied Materials & Interfaces. ISSN 1944-8244. 13(28), s. 33664–33676. doi: 10.1021/acsami.1c08236.
• Oliveira, Camila; Ribeiro Chaves, Claudilene; Bargiela, Pascal; da Gracia Carneiro da Ro, Maria; Ferreira da Silva, Antonio & Chubaci, José Fernando Diniz [Vis alle 9 forfattere av denne artikkelen] (2021). Surface studies of the chemical environment in gold nanorods supported by X-ray photoelectron spectroscopy (XPS) and ab initio calculations. Journal of Materials Research and Technology (JMR&T). ISSN 2238-7854. 15, s. 768–776. doi: 10.1016/j.jmrt.2021.08.059. Fulltekst i vitenarkiv
• Iordanidou, Konstantina & Persson, Clas (2021). Stoner ferromagnetism in hole-doped CuM(IIIA)2 with M(IIIA) = Al, Ga, and In. ACS Applied Materials & Interfaces. ISSN 1944-8244. 13(25), s. 29770–29779. doi: 10.1021/acsami.1c00403. Fulltekst i vitenarkiv
• Boström, Mathias; Esteso, Victoria; Fiedler, Johannes; Brevik, Iver Håkon; Persson, Clas & Buhmann, Stefan Yoshi [Vis alle 9 forfattere av denne artikkelen] (2021). Self-preserving ice layers on CO2 clathrate particles: Implications for Enceladus, Pluto, and similar ocean worlds. Astronomy and Astrophysics (A & A). ISSN 0004-6361. 650. doi: 10.1051/0004-6361/202040181. Fulltekst i vitenarkiv
• Gao, Jiacheng; Wu, Quansheng; Persson, Clas & Wang, Zhijun (2021). IRVSP: to obtain irreducible representations of electronic states in the VASP. Computer Physics Communications. ISSN 0010-4655. 261. doi: 10.1016/j.cpc.2020.107760.
• Huang, Dan; Ding, Lijie; Xue, Yang; Guo, Jin; Zhao, Yu-Jun & Persson, Clas (2021). Interface of Sn-doped AgAlTe2 and LiInTe2: A theoretical model of tandem intermediate band absorber . Applied Physics Letters. ISSN 0003-6951. 118(4). doi: 10.1063/5.0034852.
• Aboulfadl, Hisham; Sopiha, Kostiantyn; Keller, J; Larsen, J; Scragg, Jonathan & Persson, Clas [Vis alle 8 forfattere av denne artikkelen] (2021). Alkali dispersion in (Ag,Cu)(In,Ga)Se2 thin film solar cells – Insight from theory and experiment. ACS Applied Materials & Interfaces. ISSN 1944-8244. 13(6), s. 7188–7199. doi: 10.1021/acsami.0c20539. Fulltekst i vitenarkiv
• Iordanidou, Konstantina & Persson, Clas (2021). Optoelectronic properties of coexisting InGaZnO4 structures. Materials Science in Semiconductor Processing. ISSN 1369-8001. 121. doi: 10.1016/j.mssp.2020.105297. Fulltekst i vitenarkiv
• Sopiha, Kostiantyn; Larsen, J; Donzel-Gargand, Olivier; Khavari, F; Keller, J & Edoff, Marika [Vis alle 9 forfattere av denne artikkelen] (2020). Thermodynamic stability, phase separation and Ag grading in (Ag,Cu)(In,Ga)Se2 solar absorbers. Journal of Materials Chemistry A. ISSN 2050-7488. 8, s. 8740–8751. doi: 10.1039/d0ta00363h. Fulltekst i vitenarkiv
• Grini, Sigbjørn; Aboulfadl, Hisham; Ross, Nils; Persson, Clas; Platzer-Björkman, Charlotte & Thuvander, Mattias [Vis alle 7 forfattere av denne artikkelen] (2020). Dynamic Impurity Redistributions in Kesterite Absorbers. Physica status solidi (b). ISSN 0370-1972. 257(6). doi: 10.1002/pssb.202000062. Fulltekst i vitenarkiv
• Fiedler, Johannes; Berland, Kristian; Spallek, F.; Brevik, Iver Håkon; Persson, Clas & Buhmann, S. Y. [Vis alle 7 forfattere av denne artikkelen] (2020). Nontrivial retardation effects in dispersion forces: From anomalous distance dependence to novel traps. Physical review B (PRB). ISSN 2469-9950. 101(23). doi: 10.1103/PhysRevB.101.235424. Vis sammendrag

  In the study of dispersion forces, nonretarded, retarded, and thermal asymptotes with their distinct scaling laws are regarded as cornerstone results governing interactions at different separations. Here, we show that when particles interact in a medium, the influence of retardation is qualitatively different, making it necessary to consider the nonmonotonous potential in full. We discuss different regimes for several cases and find an anomalous behavior of the retarded asymptote. It can change sign and lead to a trapping potential.

• Esteso, V.; Carretero-Palacios, S.; MacDowell, L. G.; Fiedler, Johannes; Parsons, D. F. & Spallek, F. [Vis alle 11 forfattere av denne artikkelen] (2020). Premelting of ice adsorbed on a rock surface. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 22, s. 11362–11373. doi: 10.1039/c9cp06836h. Vis sammendrag

  Considering ice-premelting on a quartz rock surface (i.e. silica) we calculate the Lifshitz excess pressures on a four layer system with rock-ice-water-air. Our calculations give excess pressures across (1) ice layer, (2) water layer, and (3) ice-water interface for different ice and water thicknesses. We analyse equilibrium conditions where the different excess pressures take zero value, stabilised in part by repulsive Lifshitz interactions. In contrast to previous investigations which considered varying thickness of only one layer (ice or water), here we present theory allowing for simultaneous variation of both layer thicknesses for a given total thickness of ice and water, this allows multiple alternative equilibrium solutions. Consequently, the final state of a system will depend on initial conditions and may explain variation of experimental measurements of the thicknesses of water and ice layers.

• Gunnæs, Anette Eleonora; Tofan, Raluca; Berland, Kristian; Gorantla, Sandeep Madhukar; Storaas, Thomas Aarflot & Desissa, Temesgen Debelo [Vis alle 12 forfattere av denne artikkelen] (2020). Chemical stability of Ca3Co4−xO9+δ/CaMnO3−δ p–n junction for oxide-based thermoelectric generators. RSC Advances. ISSN 2046-2069. 10(9), s. 5026–5031. doi: 10.1039/c9ra07159h. Fulltekst i vitenarkiv Vis sammendrag

  An all-oxide thermoelectric generator for high-temperature operation depends on a low electrical resistance of the direct p–n junction. Ca3Co4−xO9+δ and CaMnO3−δ exhibit p-type and n-type electronic conductivity, respectively, and the interface between these compounds is the material system investigated here. The effect of heat treatment (at 900 °C for 10 h in air) on the phase and element distribution within this p–n junction was characterized using advanced transmission electron microscopy combined with X-ray diffraction. The heat treatment resulted in counter diffusion of Ca, Mn and Co cations across the junction, and subsequent formation of a Ca3Co1+yMn1−yO6 interlayer, in addition to precipitation of Co-oxide, and accompanying diffusion and redistribution of Ca across the junction. The Co/Mn ratio in Ca3Co1+yMn1−yO6 varies and is close to 1 (y = 0) at the Ca3Co1+yMn1−yO6–CaMnO3−δ boundary. The existence of a wide homogeneity range of 0 ≤ y ≤ 1 for Ca3Co1+yMn1−yO6 is corroborated with density functional theory (DFT) calculations showing a small negative mixing energy in the whole range.

• Fiedler, Johannes; Boström, Mathias; Persson, Clas; Brevik, Iver Håkon; Corkery, R. & Buhmann, S. Y. [Vis alle 7 forfattere av denne artikkelen] (2020). Full-Spectrum High-Resolution Modeling of the Dielectric Function of Water. Journal of Physical Chemistry B. ISSN 1520-6106. 124, s. 3103–3113. doi: 10.1021/acs.jpcb.0c00410. Fulltekst i vitenarkiv
• Fiedler, Johannes; Persson, Clas & Buhmann, Stefan Yoshi (2020). Spectroscopy on nanoparticles without light. Physical Review Applied. ISSN 2331-7019. 13. doi: 10.1103/PhysRevApplied.13.014025. Fulltekst i vitenarkiv
• Keller, Jan; Sopiha, Kostiantyn; Stolt, Olof; Stolt, Lars; Persson, Clas & Scragg, Jonathan [Vis alle 8 forfattere av denne artikkelen] (2020). Wide-gap (Ag,Cu)(In,Ga)Se2 solar cells with different buffer materials - A path to a better heterojunction. Progress in Photovoltaics. ISSN 1062-7995. doi: 10.1002/pip.3232.
• Iordanidou, Konstantina; Houssa, Michel & Persson, Clas (2020). Carrier-mediated ferromagnetism in two-dimensional PtS2. RSC Advances. ISSN 2046-2069. 10(2), s. 952–957 . doi: 10.1039/c9ra09756b. Fulltekst i vitenarkiv
• Berland, Kristian; Shulumba, Nina; Hellman, Olle; Persson, Clas & Løvvik, Ole Martin (2019). Thermoelectric transport trends in group 4 half-Heusler alloys. Journal of Applied Physics. ISSN 0021-8979. 126(14), s. 1–15. doi: 10.1063/1.5117288. Fulltekst i vitenarkiv Vis sammendrag

  The thermoelectric properties of 54 different group 4 half-Heusler (HH) alloys have been studied from first principles. Electronic transport was studied with density functional theory using hybrid functionals facilitated by the k⋅p method, while the temperature-dependent effective potential method was used for the phonon contributions to the figure of merit ZT. The phonon thermal conductivity was calculated including anharmonic phonon-phonon, isotope, alloy, and grain-boundary scattering. HH alloys have an XYZ composition, and those studied here are in the group 4-9-15 (Ti,Zr,Hf)(Co,Rh,Ir)(As,Sb,Bi) and group 4-10-14 (Ti,Zr,Hf)(Ni,Pd,Pt)(Ge,Sn,Pb). The electronic part of the thermal conductivity was found to significantly impact ZT and thus the optimal doping level. Furthermore, the choice of functional was found to significantly affect thermoelectric properties, particularly for structures exhibiting band alignment features. The intrinsic thermal conductivity was significantly reduced when alloy and grain-boundary scattering were accounted for, which also reduced the spread in thermal conductivity. It was found that sublattice disorder on the Z-site, i.e., the site occupied by group 14 or 15 elements, was more effective than X-site substitution, occupied by group 4 elements. The calculations confirmed that ZrNiSn, ZrCoSb, and ZrCoBi based alloys display promising thermoelectric properties. A few other n-type and p-type compounds were also predicted to be potentially excellent thermoelectric materials, given that sufficiently high charge carrier concentrations can be achieved. This study provides insight into the thermoelectric potential of HH alloys and casts light on strategies to optimize the thermoelectric performance of multicomponent alloys.

• Thiyam, Priyadarshini; Parashar, Prachi; Shajesh, Kuloth Vayalombron; Malyi, Oleksandr; Boström, Mathias & Milton, K. A. [Vis alle 9 forfattere av denne artikkelen] (2019). Effect of excess charge carriers and fluid medium on the magnitude and sign of the Casimir-Lifshitz torque . Physical review B (PRB). ISSN 2469-9950. 100(20). doi: 10.1103/PhysRevB.100.205403. Fulltekst i vitenarkiv
• Olsen, Vegard Skiftestad; Baldissera, Gustavo; Zimmermann, Christian; Granerød, Cecilie Skjold; Bazioti, Kalliopi & Galeckas, Augustinas [Vis alle 11 forfattere av denne artikkelen] (2019). Evidence of defect band mechanism responsible for band gap evolution in (ZnO)1−x(GaN)x alloys. Physical review B (PRB). ISSN 2469-9950. 100(16). doi: 10.1103/PhysRevB.100.165201. Fulltekst i vitenarkiv
• Sopiha, Kostiantyn; Malyi, Oleksandr & Persson, Clas (2019). First-principles mapping of the electronic properties of two-dimensional materials for strain-tunable nanoelectronics. ACS Applied Nano Materials. ISSN 2574-0970. 2(9), s. 5614–5624. doi: 10.1021/acsanm.9b01164.
• Zhang, Yanyan; Tang, Yuxin; Deng, Jiyang; Leow, Wan Ru; Xia, Huarong & Zhu, Zhiqiang [Vis alle 13 forfattere av denne artikkelen] (2019). Correlating the Peukert's Constant with Phase Composition of Electrode Materials in Fast Lithiation Processes. ACS Materials Letters. ISSN 2639-4979. 1(5), s. 519–525. doi: 10.1021/acsmaterialslett.9b00320.
• Hood, Samantha N; Walsh, Aron; Persson, Clas; Iordanidou, Konstantina; Huang, Dan & Kumar, Mukesh [Vis alle 10 forfattere av denne artikkelen] (2019). Status of materials and device modelling for kesterite solar cells. Journal of Physics: Energy. ISSN 2515-7655. 1. doi: 10.1088/2515-7655/ab2dda. Fulltekst i vitenarkiv
• Fiedler, Johannes; Parsons, Drew F.; Burger, Friedrich A.; Thiyam, Priydarshini; Walter, Michael & Brevik, Iver Håkon [Vis alle 9 forfattere av denne artikkelen] (2019). Impact of effective polarisability models on the near-field interaction of dissolved greenhouse gases at ice and air interfaces. Physical Chemistry, Chemical Physics - PCCP. ISSN 1463-9076. 21(38), s. 21296–21304. doi: 10.1039/c9cp03165k. Vis sammendrag

  We present a theory for Casimir–Polder forces acting on greenhouse gas molecules dissolved in a thin water film. Such a nano-sized film has been predicted to arise on the surface of melting ice as stabilized by repulsive Lifshitz forces. We show that different models for the effective polarisability of greenhouse gas molecules in water lead to different predictions for how Casimir–Polder forces influence their extractions from the melting ice surface. For instance, in the most intricate model of a finite-sized molecule inside a cavity, dispersion potentials push the methane molecules towards the ice surface whereas the oxygen typically will be attracted towards the closest interface (ice or air). Previous models for effective polarisability had suggested that O2 would also be pushed towards the ice surface. Release of greenhouse gas molecules from the surface of melting ice can potentially influence climate greenhouse effects. With this model, we show that some molecules cannot escape from water as single molecules. Due to the contradiction of the results and the escape dynamics of gases from water, we extended the models to describe bubble filled with several molecules increasing their buoyancy force.

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• Mendonça, Bianca; Chubaci, J. f. d.; Matsuoka, M.; Ferreira da Silva, Antonio; Zambom, Luis & Mansano, Ronaldo [Vis alle 8 forfattere av denne artikkelen] (2021). Dependence of the electronic and optical properties of thin film TiO2 film with oxygen partial pressure.
• Sopiha, Kostiantyn; Larsen, Jes; Keller, Jan; Edoff, Marika; Platzer-Björkman, Charlotte & Persson, Clas [Vis alle 7 forfattere av denne artikkelen] (2020). First-principles analysis of band offsets, phase stability, and alkali incorporation in (Ag,Cu)(In,Ga)Se2 solar cells.
• Sopiha, Kostiantyn; Grini, Sigbjørn; Platzer-Björkman, Charlotte; Vines, Lasse & Persson, Clas (2020). Strong interplay between Na-and O-related defects in Cu-based chalcogenides.
• Løvvik, Ole Martin; Berland, Kristian; Remonato, Filippo; Sagvolden, Espen; Flage-Larsen, Espen & Schrade, Matthias [Vis alle 13 forfattere av denne artikkelen] (2019). Screening thermoelectric materials with ab initio atomistic modelling and machine learning techniques.
• Zhang, Yanyan; Tang, Yuxin; Deng, Jiyang; Leow, Wan Ru; Xia, Huarong & Zhu, Zhiqiang [Vis alle 13 forfattere av denne artikkelen] (2019). Cover page: ACS Materials Letters, Volume 1, Issue 5, November 4, 2019.
• Sopiha, Kostiantyn; Keller, Jan; Larsen, Jes K.; Edoff, Marika; Persson, Clas & Scragg, Jonathan (2019). Band offsets, phase decomposition, and grading in (Ag,Cu)(In,Ga)Se2 solar cells.
• Fiedler, Johannes; Persson, Clas & Buhmann, Stefan Yoshi (2019). Spectroscopy of nanoparticles without light.
• Fiedler, Johannes; Persson, Clas; Boström, Mathias & Buhmann, Stefan Yoshi (2019). The dispersion trap.
• Høylo-Rosenberg, Jørn-Marcus; Løvvik, Ole Martin & Persson, Clas (2022). An ab initio study of the band gaps of high-entropy silicides based on FeSi2. Universitetet i Oslo. Vis sammendrag

  In this work we have set out to examine the band gaps of potential high-entropy stabilized transition metal silicides, based on the FeSi2 semiconductor. Here, we have performed a first principles study utilizing density functional theory in combination with the special quasi-random structures method. The band gaps has been evaluated primarily with the PBE GGA functional, but also the SCAN meta-GGA functional and hybrid functional HSE06 has been applied in this project. Potential alloys has been examined by generating a set of distinct supercells of the FeSi2 structure, where the iron sites are populated quasi-randomly by a combination of 3d transition metals. The alloys we have studied in this project are comprised of combinations of Cr, Fe, Mn, Ni, Co and Ti, most emphasis has been put on the Cr-Fe-Mn-Ni-Si system. In the (CrFeMnNi)Si2 composition, we can report several semiconducting supercells with band gaps ranging between 0 - 0.05 eV using PBE GGA. The band gaps displayed significant spin polarization, in the spin up direction most supercells pointed to a gap around 0.3 eV. Contrary, the band gaps in spin down varied between 0 - 0.05 eV. Accordingly, we found a finite magnetic moment in this alloy equal to 0.083 mu_B, this was attributed mainly to chromium and manganese atoms in the lattice. Successive simulations of alloys based on the Cr-Fe-Mn-Ni-Si system with non-equimolar distribution of 3d elements, resulted most frequently in half-metallic structures with a spin up band gap ranging between 0.1 eV and 0.5 eV. Of the different compositions we tested, the ones either rich in manganese and/or poor in chromium showed the most promise with respect to the band gap. In particular, we report a PBE total band gap equal to 0.1 eV in the Cr3Fe5Mn5Ni3Si32 composition. Lastly, we looked at compositions where either Cr, Mn or Ni were replaced by either cobalt or titanium. This yielded predominately metallic compounds, where the lack of band gaps could be ascribed to defect states at the band edges.

• Hinderaker, Mariel Aulie & Persson, Clas (2022). DFT Calculations of Metal Oxide Semiconductors - An Improvement of Optical and Electronic Property Calculations. Universitetet i Oslo.
• Persson, Clas & Tariq, Aayesha (2022). First-principle calculations of ferroelectric properties of HfO2 and ZrO2. Universitetet i Oslo.
• Persson, Clas & Aulie Hinderaker, Mariel (2022). DFT Calculations of Metal Oxide Semiconductors - An Improvement of Optical and Electronic Property Calculations. Universitetet i Oslo.
• Nyberg, Fredrik; Løvvik, Ole Martin & Persson, Clas (2020). Ab initio calculation of the coefficient of thermal expansion and the secondary pyroelectric vector. Universitetet i Oslo.
• Mjærum, Dagfinn Olaf Øvrevik; Persson, Clas; Berland, Kristian & Løvvik, Ole Martin (2019). Layer Stacking and Electronic Properties of Hexagonal Covalent Organic Frameworks - A Computational Investigation with van der Waals Density Functional Theory. Universitetet i Oslo. Vis sammendrag

  We have calculated the electronic properties and layer stacking patterns for a group of twelve hexagonal covalent organic frameworks. This has been done in order to explore this group of materials on a fundamental level and aim to lay the ground work for further studies, which will focus on assessing these frameworks as useful materials for electronic and optoelectronic devices. To explore these materials, we have deployed numerical density functional theory calculations. A Van der Waals density functional is used to describe non-local correlation effects that give rise to stabilizing van der Waals forces, essential in layered systems. We found that all the materials prefer to stack in specific configurations close to AA-stacking, where subsequent layers are placed directly on-top of each other. We also found that the materials exhibit dispersion in the out-of-plane direction when we go from two-dimensional single layers to three-dimensional stacks.

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