Research Output

Research Output per year

1999 2020

• 30 Article
• 8 Working paper
• 7 Conference contribution
• 1 Chapter
• 2 More
  • 1 Meeting Abstract
  • 1 Literature review

Research Output per year

Research Output per year

Search results

• Article

  Alkali Postdeposition Treatment-Induced Changes of the Chemical and Electronic Structure of Cu(In,Ga)Se₂ Thin-Film Solar Cell Absorbers: A First-Principle Perspective

  Malitckaya, M., Kunze, T., Komsa, H. P., Havu, V., Handick, E., Wilks, R. G., Bär, M. & Puska, M. J., 23 Jan 2019, In : ACS Applied Materials and Interfaces. 11, 3, p. 3024-3033 10 p.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Valence bands
  • Thin film solar cells
  • Electronic structure
  • Band structure
  • Alkalies
  5 Citations (Scopus)

  141 Downloads (Pure)

• All-electron density functional theory and time-dependent density functional theory with high-order finite elements

  Lehtovaara, L., Havu, V. & Puska, M., 2009, In : Journal of Chemical Physics. 131, 5, p. 1-10 10 p., 054103.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Density functional theory
  • Carrier concentration
  • density functional theory
  • mesh
  • Mesh generation
  44 Citations (Scopus)

  25 Downloads (Pure)

• All-electron time-dependent density functional theory with finite elements: Time-propagation approach

  Lehtovaara, L., Havu, V. & Puska, M., 2011, In : Journal of Chemical Physics. 135, 15, p. 1-8 8 p., 154104.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Density functional theory
  • Electrons
  • density functional theory
  • Boundary conditions
  • boundary conditions
  14 Citations (Scopus)

  63 Downloads (Pure)

• Analysis of a bilinear finite element for shallow shells I: Approximation of inextensional deformations

  Havu, V. & Pitkäranta, J., 2002, In : Mathematics of Computation. 71, p. 923-943

  Research output: Contribution to journal › Article › Scientific › peer-review

  10 Citations (Scopus)

• Analysis of a bilinear finite element for shallow shells II

  Havu, V. & Pitkäranta, J., 2003, In : Mathematics of Computation. 72, 244, p. 1635-1653

  Research output: Contribution to journal › Article › Scientific › peer-review

• An Analysis of Asymptotic Consistency Error in a Parameter Dependent Model Problem

  Havu, V., 2003, In : CALCOLO. 40, 2, p. 121-130

  Research output: Contribution to journal › Article › Scientific › peer-review

  6 Citations (Scopus)

• Conductivity of AuCl4-Functionalized Carbon Nanotube Networks

  Ketolainen, T., Havu, V. & Puska, M. J., 2 Mar 2017, In : Journal of Physical Chemistry C. 121, 8, p. 4627-4634 8 p.

  Research output: Contribution to journal › Article › Scientific › peer-review
  4 Citations (Scopus)

• Direct Minimization for Ensemble Electronic Structure Calculations

  Baarman, K., Havu, V. & Eirola, T., 1 Mar 2016, In : JOURNAL OF SCIENTIFIC COMPUTING. 66, 3, p. 1218-1233 16 p.

  Research output: Contribution to journal › Article › Scientific › peer-review

  • Electronic structure
  • Electronic Structure
  • Ensemble
  • Optimization
  • Electronics

• Effect of Alkali Metal Atom Doping on the CuInSe2-Based Solar Cell Absorber

  Malitckaya, M., Komsa, H. P., Havu, V. & Puska, M. J., 27 Jul 2017, In : Journal of Physical Chemistry C. 121, 29, p. 15516-15528 13 p.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Alkali Metals
  • Alkali metals
  • Doping (additives)
  • alkali metals
  • Solar cells
  67 Citations (Scopus)

  169 Downloads (Pure)

• Efficient O(N) Integration For All-Electron Electronic Structure Calculation Using Numeric Basis Functions

  Havu, V., Blum, V., Havu, P. & Scheffler, M., 2009, In : Journal of Computational Physics. 228, 22, p. 8367-8379

  Research output: Contribution to journal › Article › Scientific › peer-review

  262 Citations (Scopus)

• Electronic Transport Properties of Carbon-Nanotube Networks: The Effect of Nitrate Doping on Intratube and Intertube Conductances

  Ketolainen, T., Havu, V., Jónsson, E. & Puska, M. J., 15 Mar 2018, In : Physical Review Applied. 9, 3, p. 1-13 034010.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • nitrates
  • carbon nanotubes
  • transport properties
  • electronics
  • molecules
  5 Citations (Scopus)

  91 Downloads (Pure)

• Electron transport through quantum wires and point contacts

  Havu, P., Puska, M. J., Nieminen, R. M. & Havu, V., 17 Dec 2004, In : Physical Review B. 70, 23, p. 1-4 4 p., 233308.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Semiconductor quantum wires
  • Electron Transport
  • Point contacts
  • quantum wires
  • Spin polarization
  51 Citations (Scopus)

  175 Downloads (Pure)

• ELSI — An open infrastructure for electronic structure solvers

  Yu, V. W. Z., Campos, C., Dawson, W., García, A., Havu, V., Hourahine, B., Huhn, W. P., Jacquelin, M., Jia, W., Keçeli, M., Laasner, R., Li, Y., Lin, L., Lu, J., Moussa, J., Roman, J. E., Vázquez-Mayagoitia, Á., Yang, C. & Blum, V., Nov 2020, In : Computer Physics Communications. 256, p. 1-16 16 p., 107459.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  • Electronic structure
  • electronic structure
  • scaling
  • matrices
  • Hamiltonians
  1 Citation (Scopus)

• Enhancing conductivity of metallic carbon nanotube networks by transition metal adsorption

  Ketolainen, T., Havu, V. & Puska, M., 2015, In : Journal of Chemical Physics. 142, 5, p. 1-9 9 p., 054705.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Transition metals
  • Carbon Nanotubes
  • Atoms
  • Adsorption
  • Fermi level
  9 Citations (Scopus)

  200 Downloads (Pure)

• Finite-element implementation for electron transport in nanostructures

  Havu, P., Havu, V., Puska, M. J., Hakala, M. H., Foster, A. S. & Nieminen, R. M., 2006, In : Journal of Chemical Physics. 124, 5, p. 1-8 8 p., 054707.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Hafnium
  • Nanosystems
  • Electron Transport
  • Density functional theory
  • Transport properties
  15 Citations (Scopus)

  9 Downloads (Pure)

• First-Principles Modeling of Point Defects and Complexes in Thin-Film Solar-Cell Absorber CuInSe2

  Malitckaya, M., Komsa, H. P., Havu, V. & Puska, M. J., 1 Jun 2017, In : Advanced Electronic Materials. 3, 6, p. 1-9 1600353.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Point defects
  • Thin film solar cells
  • Indium
  • Photoluminescence
  • Chemical potential
  18 Citations (Scopus)

  120 Downloads (Pure)

• Heavy Alkali Treatment of Cu(In,Ga)Se₂ Solar Cells: Surface versus Bulk Effects

  Siebentritt, S., Avancini, E., Bär, M., Bombsch, J., Bourgeois, E., Buecheler, S., Carron, R., Castro, C., Duguay, S., Félix, R., Handick, E., Hariskos, D., Havu, V., Jackson, P., Komsa, H. P., Kunze, T., Malitckaya, M., Menozzi, R., Nesladek, M., Nicoara, N. & 13 others, Puska, M., Raghuwanshi, M., Pareige, P., Sadewasser, S., Sozzi, G., Tiwari, A. N., Ueda, S., Vilalta-Clemente, A., Weiss, T. P., Werner, F., Wilks, R. G., Witte, W. & Wolter, M. H., 1 Jan 2020, In : Advanced Energy Materials. p. 1-15 15 p., 1903752.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  • Alkalies
  • Solar cells
  • Grain boundaries
  • Electronic structure
  • chalcopyrite
  19 Citations (Scopus)

• Hybrid functional study of band structures of GaAs_1-xN_x and GaSb_1-xN_x Alloys

  Virkkala, V., Havu, V., Tuomisto, F. & Puska, M. J., Feb 2012, In : Physical Review B. 85, 8, p. 1-8 8 p., 085134.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Band structure
  • Energy gap
  • Conduction bands
  • Density functional theory
  • Bending (forming)
  25 Citations (Scopus)

  284 Downloads (Pure)

• Large-scale surface reconstruction energetics of Pt(100) and Au(100) by all-electron density functional theory

  Havu, P., Blum, V., Havu, V., Rinke, P. & Scheffler, M., 2010, In : Physical Review B. 82, p. 1-4 161418.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Density functional theory
  • Carrier concentration
  • Surface reconstruction
  • density functional theory
  • Nanostructures
  39 Citations (Scopus)

  294 Downloads (Pure)

• Modeling Bi-induced changes in the electronic structure of GaAs 1-xBix alloys

  Virkkala, V., Havu, V., Tuomisto, F. & Puska, M. J., 5 Dec 2013, In : Physical Review B. 88, 23, p. 1-6 6 p., 235201.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • gallium arsenide
  • Electronic structure
  • Energy gap
  • electronic structure
  • interactions
  19 Citations (Scopus)

  143 Downloads (Pure)

• Native Point Defect Energetics in GaSb: enabling p-type conductivity of undoped GaSb

  Virkkala, V., Havu, V., Tuomisto, F. & Puska, M. J., 1 Oct 2012, In : Physical Review B. 86, 14, p. 1-7 7 p., 144101.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Point defects
  • energy of formation
  • point defects
  • Fermi level
  • Density functional theory
  27 Citations (Scopus)

  157 Downloads (Pure)

• Nonadiabatic Ehrenfest molecular dynamics within the projector augmented-wave method

  Ojanperä, A., Havu, V., Lehtovaara, L. & Puska, M., 2012, In : Journal of Chemical Physics. 136, 14, p. 1-9 9 p., 144103.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Molecular dynamics
  • projectors
  • molecular dynamics
  • Hydrogen
  • Sodium chloride
  21 Citations (Scopus)

  20 Downloads (Pure)

• Non-Equilibrium Electron Transport in Two-Dimensional Nano-Structures Modeled by Green's Functions and the Finite-Element-Method

  Havu, P., Havu, V., Puska, M. J. & Nieminen, R. M., 2004, In : Physical Review B. 69

  Research output: Contribution to journal › Article › Scientific › peer-review

• Nonequilibrium electron transport in two-dimensional nanostructures modeled using Green's functions and the finite-element method

  Havu, P., Havu, V., Puska, M. J. & Nieminen, R. M., 19 Mar 2004, In : Physical Review B. 69, 11, p. 1-13 13 p., 115325.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Electron Transport
  • Nanostructures
  • Green's function
  • finite element method
  • Green's functions
  34 Citations (Scopus)

  163 Downloads (Pure)

• Ohuiden kuorien numeeriset menetelmät

  Havu, V., 2006, In : Rakenteiden mekaniikka. 39, 1, p. 19-26

  Research output: Contribution to journal › Article › Professional

• Origin of band gap bowing in dilute GaAs_1-xN_x and GaP_1-xN_x alloys: a real-space view

  Virkkala, V., Havu, V., Tuomisto, F. & Puska, M. J., Jul 2013, In : Physical Review B. 88, 3, p. 1-6 6 p., 035204.

  Research output: Contribution to journal › Article › Scientific › peer-review

  Open Access

  File

  • Bending (forming)
  • Energy gap
  • Nitrogen
  • nitrogen
  • Conduction bands
  20 Citations (Scopus)

  302 Downloads (Pure)

• Robust acceleration of self consistent field calculations for density functional theory

  Baarman, K., Eirola, T. & Havu, V., 2011, In : Journal of Chemical Physics. 134, 13

  Research output: Contribution to journal › Article › Scientific › peer-review
  7 Citations (Scopus)

• The Cayley transform as a time discretization scheme

  Malinen, J. & Havu, V., 2007, In : Numerical Functional Analysis and Optimization. 28, 7-8, p. 825-851

  Research output: Contribution to journal › Article › Scientific › peer-review
  31 Citations (Scopus)

• The ELPA library: scalable parallel eigenvalue solutions for electronic structure theory and computational science

  Marek, A., Blum, V., Johanni, R., Havu, V., Lang, B., Auckenthaler, T., Heinecke, A., Bungartz, H-J. & Lederer, H., 2014, In : Journal of physics: Condensed matter. 26, 21

  Research output: Contribution to journal › Article › Scientific › peer-review
  109 Citations (Scopus)

• Three real-space discretization techniques in electronic structure calculations

  Torsti, T., Eirola, T., Enkovaara, J., Hakala, T., Havu, P., Havu, V., Höynälänmaa, T., Ignatius, J., Lyly, M., Makkonen, I., Rantala, T., Ruokolainen, J., Ruotsalainen, K., Räsänen, E., Saarikoski, H. & Puska, M. J., Apr 2006, In : PHYSICA STATUS SOLIDI B: BASIC SOLID STATE PHYSICS. 243, 5, p. 1016-1053 28 p.

  Research output: Contribution to journal › Article › Scientific › peer-review
  88 Citations (Scopus)
• Chapter

  Grid-Based Projector-Augmented Wave Method

  Hakala, S., Enkovaara, J., Havu, V., Yan, J., Li, L., O'Grady, C. & Nieminen, R. M., 19 Feb 2016, Electronic Structure Calculations on Graphics Processing Units: From Quantum Chemistry to Condensed Matter Physics. Walker, R. & Götz, A. (eds.). Wiley, p. 191-210 20 p.

  Research output: Chapter in Book/Report/Conference proceeding › Chapter › Scientific › peer-review
  1 Citation (Scopus)
• Conference contribution

  Convergence of the MITC4 Shell Element

  Pitkäranta, J., Hakula, H., Havu, V. & Malinen, M., 2002, The Fifth World Congress on Computational Mechanics (WCCM V), July 7-12, Vienna, Austria. Mang, M. A., Rammerstorfer, F. G. & Eberhardsteiner, J. (eds.). Wien: Vienna University of Technology

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Scientific › peer-review

• First-principles modeling of alkali metal post deposition treatment effects in CIGS solar cells

  Fedina, M., Komsa, H-P., Havu, V. & Puska, M. J., 2017, 2017 IEEE 44TH PHOTOVOLTAIC SPECIALIST CONFERENCE (PVSC). IEEE, p. 2070-2072 3 p. (IEEE Photovoltaic Specialists Conference).

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Scientific › peer-review

• Laplace and Cayley transforms - an approximation point of view

  Havu, V. & Malinen, J., 2005, 44th IEEE Conference on Decision and Control and European Control Conference ECC 2005, CDC-ECC'05, Seville, Spain, 12-15 December, 2005. p. 5971

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Scientific › peer-review

  7 Citations (Scopus)

• MITC4-kuorielementin konvergenssiominaisuudet

  Havu, V. & Hakula, H., 2003, VIII Suomen mekaniikkapäivät, Espoo 12.-13.6.2003. Råbäck, P., Santaoja, K. & Stenberg, R. (eds.). Espoo: TKK, p. 533-539

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Scientific › peer-review

• On sensitive shell under different loadings

  Havu, V. & Hakula, H., 2004, 4th European Congress on Computational Methods in Applied Sciences and Engineering, ECCOMAS 2004, Jyväskylä, 2004. Neittaanmäki, P., Rossi, T., Korotov, S., Onate, E., Periaux, J. & Knörzer, D. (eds.). Jyväskylä: ECCOMAS, Jyväskylän yliopisto

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Scientific › peer-review

• Parallel electronic structure calculations using multiple graphics processing units (GPUs)

  Hakala, S., Havu, V., Enkovaara, J. & Nieminen, R., 2013, Applied Parallel and Scientific Computing - 11th International Conference, PARA 2012, Revised Selected Papers. Vol. 7782 LNCS. p. 63-76 14 p. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); vol. 7782 LNCS).

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Scientific › peer-review

  • Graphics Processing Unit
  • Electronic structure
  • Electronic Structure
  • Graphics processing unit
  • Scaling
  15 Citations (Scopus)

• Prediction of Ground Frost Thawing

  Eirola, T., Havu, V. & Junes, H., 2004, The 50th European Study Group with Industry (ESGI), Espoo 24.-28.5.2004 (ECMI50). CSC, p. 53-60

  Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Scientific › peer-review
• Literature review

  Ab initio molecular simulations with numeric atom-centered orbitals

  Blum, V., Gehrke, R., Hanke, F., Havu, P., Havu, V., Ren, X., Reuter, K. & Scheffler, M., Nov 2009, In : Computer Physics Communications. 180, 11, p. 2175-2196 22 p.

  Research output: Contribution to journal › Literature review › Scientific › peer-review
• Meeting Abstract

  Large-scale benchmark of electronic structure solvers with the ELSI infrastructure

  Yu, V., Dawson, W., Garcia, A., Havu, V., Hourahine, B., Huhn, W., Jacquelin, M., Jia, W., Keceli, M., Laasner, R., Li, Y., Lin, L., Lu, J., Roman, J., Vazquez-Mayagoitia, A., Yang, C. & Blum, V., 31 Mar 2019, In : Abstracts of papers of the American Chemical Society. 257, 1 p.

  Research output: Contribution to journal › Meeting Abstract › Scientific › peer-review
• Working paper

  A benchmark study of elliptic and hyperbolic shells of revolution

  Havu, V., Hakula, H. & Tuominen, T., 2003, Espoo, p. 15, (Helsinki University of Technology Institute of Mathematics Research Reports; no. A456).

  Research output: Working paper › Professional

• Analysis of a bilinear finite element for shallow shells I: approximation of inextensional deformations

  Havu, V. & Pitkäranta, J., 2001, Espoo, p. 23, (Helsinki University of Technology Institute of Mathematics Research Reports; no. A430).

  Research output: Working paper › Professional

  10 Citations (Scopus)

• Analysis of a bilinear finite element for shallow shells II: consistency error

  Havu, V. & Pitkäranta, J., 2001, Espoo, p. 19, (Helsinki University of Technology Institute of Mathematics Research Reports; no. A433).

  Research output: Working paper › Professional

  8 Citations (Scopus)

• Analysis of reduced finite element schemes in parameter dependent elliptic problems

  Havu, V., 2001, Espoo, p. 99, (Helsinki University of Technology Institute of Mathematics Research Reports; no. A442).

  Research output: Working paper › Professional

• An analysis of asymptotic consistency error in a parameter dependent model problem

  Havu, V., 2001, Espoo, p. 11, (Helsinki University of Technology Institute of Mathematics Research Reports; no. A434).

  Research output: Working paper › Professional

  6 Citations (Scopus)

• An analysis of finite locking in a parameter dependent model problem

  Havu, V. & Pitkäranta, J., 1999, Espoo, p. 22, (Helsinki University of Technology Institute of Mathematics Research Reports; no. A420).

  Research output: Working paper › Professional

• Approximation of the Laplace transform by the Cayley transform

  Havu, V. & Malinen, J., 2004, Espoo, p. 22, (Helsinki University of Technology, Institute of mathematics, Research Reports; no. A480).

  Research output: Working paper › Professional

• Computational Problems in Physics 2005 - Group Reports

  Eirola, T., Havu, V., Jauho, A-P. & von Pfaler, J., 2005, Espoo, p. 82, (Helsinki University of Technology. Institute of Mathematics, Research Reports C; no. C018).

  Research output: Working paper › Professional