• Anisotropic contribution to the van der Waals and the Casimir-Polder energies for CO2 and CH4 molecules near surfaces and thin film 

      Thiyam, Priyadarshini; Parashar, Prachi; Shajesh, K. V.; Persson, Clas; Schaden, Martin; Brevik, Iver Håkon; Parsons, Drew F.; Milton, Kimball A.; Malyi, Oleksandr; Boström, Mathias (Journal article; Peer reviewed, 2015)
      In order to understand why carbon dioxide ( CO 2 ) and methane ( CH 4 ) molecules interact differently with surfaces, we investigate the Casimir-Polder energy of a linearly polarizable CO 2 molecule and an isotropically ...
    • Casimir forces in a plasma: possible connections to Yukawa potentials 

      Ninham, Barry W.; Boström, Mathias; Persson, Clas; Brevik, Iver Håkon; Buhmann, Stefan Yoshi; Sernelius, Bo. E. (Journal article; Peer reviewed, 2014)
      We present theoretical and numerical results for the screened Casimir effect between perfect metal surfaces in a plasma. We show how the Casimir effect in an electron-positron plasma can provide an important contribution ...
    • Casimir quantum levitation tuned by means of material properties and geometries 

      Dou, Maofeng; Lui, F; Boström, Mathias; Brevik, Iver Håkon; Persson, Clas (Journal article; Peer reviewed, 2014)
      The Casimir force between two surfaces is attractive in most cases. Although stable suspension of nano-objects has been achieved, the sophisticated geometries make them difficult to be merged with well-established thin ...
    • Chemical stability of Ca3Co4−xO9+δ/CaMnO3−δ p–n junction for oxide-based thermoelectric generators 

      Gunnæs, Anette Eleonora; Tofan, Raluca; Berland, Kristian; Gorantla, Sandeep Madhukar; Storaas, Thomas Aarflot; Desissa, Temesgen Debelo; Schrade, Matthias; Persson, Clas; Einarsrud, Mari-Ann; Wiik, Kjell; Norby, Truls Eivind; Kanas, Nikola (Peer reviewed; Journal article, 2020)
      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, ...
    • Dispersion forces in inhomogeneous planarly layered media: A one-dimensional model for effective polarizabilities 

      Fiedler, Johannes; Spallek, Fabian; Thiyam, Priyadarshini; Persson, Clas; Boström, Mathias; Walter, Michael; Buhmann, Stefan Yoshi (Journal article; Peer reviewed, 2019)
      Dispersion forces such as van der Waals forces between two microscopic particles, the Casimir-Polder forces between a particle and a macroscopic object, or the Casimir force between two dielectric objects are well studied ...
    • Distance-dependent sign reversal in the Casimir-Lifshitz torque 

      Thiyam, Priyadarshini; Parashar, Prachi; Shajesh, Kuloth Vayalombron; Malyi, Oleksandr; Boström, Mathias; Milton, Kimball A.; Brevik, Iver Håkon; Persson, Clas (Journal article; Peer reviewed, 2018)
      The Casimir-Lifshitz torque between two biaxially polarizable anisotropic planar slabs is shown to exhibit a nontrivial sign reversal in its rotational sense. The critical distance $a_c$ between the slabs that marks this ...
    • Effect of excess charge carriers and fluid medium on the magnitude and sign of the Casimir-Lifshitz torque 

      Thiyam, Priyadarshini; Parashar, Prachi; Shajesh, Kuloth Vayalombron; Malyi, Oleksandr; Boström, Mathias; Milton, K. A.; Brevik, Iver Håkon; Forsman, Jan; Persson, Clas (Journal article; Peer reviewed, 2019)
      Last year, we reported a perturbative theory of the Casimir-Lifshitz torque between planar biaxially anisotropic materials in the retarded limit [Thiyam et al., Phys. Rev. Lett. 120, 131601 (2018)], which is applied here ...
    • Effective polarisability models 

      Fiedler, Johannes; Thiyam, Priyadarshini; Kurumbail, Anurag; Burger, Friedrich A.; Walter, Michael; Persson, Clas; Brevik, Iver Håkon; Parsons, Drew F.; Boström, Anders Mathias; Buhmann, Stefan Yoshi (Journal article; Peer reviewed, 2017)
      Theories for the effective polarizability of a small particle in a medium are presented using different levels of approximation: we consider the virtual cavity, real cavity, and the hard-sphere models as well as a continuous ...
    • Finite-size-dependent dispersion potentials between atoms and ions dissolved in water 

      Thiyam, Priyadarshini; Boström, Mathias; Persson, Clas; Parsons, Drew F.; Brevik, Iver Håkon; Sernelius, Bo. E. (Journal article; Peer reviewed, 2014)
      A non-expanded theory is used for dispersion potentials between atoms and ions dissolved in a medium. The first-order dispersion interaction between two atoms in an excited state must account for the fact that the two atoms ...
    • Fluid sensitive nanoscale switching with quantum levitation controlled by a-Sn/b-Sn phase transition 

      Boström, Anders Mathias; Dou, Maofeng; Malyi, Oleksandr; Parashar, Prachi; Parsons, Drew F.; Brevik, Iver Håkon; Persson, Clas (Journal article, 2018)
      We analyze the Lifshitz pressure between silica and tin separated by a liquid mixture of bromobenzene and chlorobenzene. We show that the phase transition from semimetallic α−Sn to metallic β−Sn can switch Lifshitz forces ...
    • Ice particles sink below the water surface due to a balance of salt, van der Waals and buoyancy forces 

      Thiyam, Priyadarshini; Fiedler, Johannes; Buhmann, Stefan Yoshi; Persson, Clas; Brevik, Iver Håkon; Boström, Mathias; Parsons, Drew F. (Journal article; Peer reviewed, 2018)
      According to the classical Archimedes’ principle, ice floats in water and has a fraction of its volume above the water surface. However, for very small ice particles, other competing forces such as van der Waals forces due ...
    • Lattice thermal conductivity of TixZryHf1−x−yNiSn half-Heusler alloys calculated from first principles: Key role of nature of phonon modes 

      Eliassen, Simen Nut Hansen; Katre, Anikta; Madsen, Georg; Persson, Clas; Løvvik, Ole Martin; Berland, Kristian (Journal article; Peer reviewed, 2017)
      In spite of their relatively high lattice thermal conductivity κℓ, the XNiSn (X=Ti, Zr, or Hf) half-Heusler compounds are good thermoelectric materials. Previous studies have shown that κℓ can be reduced by sublattice ...
    • Lifshitz interaction can promote ice growth at water-silica interfaces 

      Boström, Mathias; Malyi, Oleksandr; Parashar, Prachi; Shajesh, Kuloth Vayalombron; Thiyam, Priyadarshini; Milton, Kimball A.; Persson, Clas; Parsons, Drew F.; Brevik, Iver Håkon (Journal article; Peer reviewed, 2017)
      At air-water interfaces, the Lifshitz interaction by itself does not promote ice growth. On the contrary, we find that the Lifshitz force promotes the growth of an ice film, up to 1–8 nm thickness, near silica-water ...
    • Non-perturbative theory of dispersion interactions 

      Boström, Mathias; Thiyam, Priyadarshini; Persson, Clas; Parsons, Drew F.; Buhmann, Stefan Yoshi; Brevik, Iver Håkon; Sernelius, Bo. E. (Journal article; Peer reviewed, 2015)
      Some open questions exist with fluctuation-induced forces between extended dipoles. Conventional intuition derives from large-separation perturbative approximations to dispersion force theory. Here, we present a full ...
    • Nonperturbative theory for the dispersion self-energy of atoms 

      Thiyam, Priyadarshini; Persson, Clas; Brevik, Iver Håkon; Sernelius, Bo. E.; Boström, Mathias (Journal article; Peer reviewed, 2014)
      We go beyond the approximate series expansions used in the dispersion theory of finite-size atoms. We demonstrate that a correct, and nonperturbative, theory dramatically alters the dispersion self-energies of atoms. The ...
    • Orientational dependence of the van der Waals interactions for finite-sized particles 

      Fiedler, Johannes; Persson, Clas; Boström, Mathias; Buhmann, Stefan Yoshi (Journal article, 2018)
      Dispersion forces, especially van der Waals forces as interactions between neutral and polarizable particles act at small distances between two objects. Their theoretical origin lies in the electromagnetic interaction ...
    • The influence of Lifshitz forces and gas on premelting of ice within porous materials 

      Boström, Mathias; Malyi, Oleksandr; Thiyam, Priyadarshini; Berland, Kristian; Brevik, Iver Håkon; Persson, Clas; Parsons, Drew F. (Journal article; Peer reviewed, 2016)
      Premelting of ice within pores in earth materials is shown to depend on the presence of vapor layers. For thick vapor layers between ice and pore surfaces, a nanosized water sheet can be formed due to repulsive Lifshitz ...
    • The role of grain boundary scattering in reducing the thermal conductivity of polycrystalline XNiSn (X=Hf, Zr, Ti) half-Heusler alloys 

      Schrade, Matthias; Berland, Kristian; Eliassen, Simen Nut Hansen; Guzik, Matylda Natalia; Echevarria-Bonet, Cristina; Sørby, Magnus Helgerud; Jenus, Petra; Hauback, Bjørn; Tofan, Raluca; Gunnæs, Anette Eleonora; Persson, Clas; Løvvik, Ole Martin; Finstad, Terje (Journal article; Peer reviewed, 2017)
      Thermoelectric application of half-Heusler compounds suffers from their fairly high thermal conductivities. Insight into how effective various scattering mechanisms are in reducing the thermal conductivity of fabricated ...