News
February 1, 2024:
This year, we will host the annual conference of the Research School for Training the Next Generation of Micro- and Nanotechnology Researchers in Norway (TNNN)
Watch for updates on the TNNN conference website, or contact me if you are interested and want to know more!
Note: This conference is part of a week-long science extravaganza in Oslo and Forskningsparken. The full programme includes:
1) Nordic NanoLab User Meeting (NNUM 2024), June 3-4, 2024
2) The Sensor Decade 2024, June 5-6, 2024
3) TNNN conference, June 6-8, 2024
December 20, 2023
Our latest work on electron-phonon and electron-magnon interactions in Ni(111) has just been accepted for publication in PRB! You can find the full version on ArXiV.
Well done to Håkon Røst and everyone else invovled in this project!
December 4, 2023
Our recent work (as part of a large collaboration lead by Federico Mazzola) has just been published in Nature Comms Materials. The work is called `Dynamics and resilience of the unconventional charge density wave in ScV6Sn6 bilayer kagome metal' and can be view on the journal website by clicking the link behind the title -- or here on ArXiv. Well done to everyone involved!
November 3, 2023
Our recent work on vicinal surfaces of bismuth has now been published in PRB! The paper relies on spin-resolved data from our nanoESCA instrument, as well as synchrotron data from ELETTRA. Well done to everyone involved!
September 1, 2023
Our Quantum Technology whitepaper is now published!
"Quantum Technology in Norway: Proposal for a National Funding Strategy"
by F. Massel (USN), J. Danon (NTNU), S. Ali (Simula), K. Børkje (USN), F. G. Fuchs (SINTEF/UiO), N. Larsen (UiO), S. Selstø (OsloMet), K. Tywoniuk (UiB), S. Viefers (UiO), J. W. Wells (UiO).
Please read and share any comments with me or the other co-authors!
August 10, 2023
Our most recent article "Phonon-Mediated Quasiparticle Lifetime Renormalizations in Few-Layer Hexagonal Boron Nitride" is now published in Nanoletters. Thanks for the collaboration Håkon, Simon, Anna Cecilie, Jinbang, Ayaz, Takashi, Kenji, Branson, Bodil, Jerzy and Federico!
[Also published as a `Top Story' by ELETTRA:
https://www.elettra.eu/science/top-stories/probing-the-arrangement-of-subsurface-dopants-in-a-silicon-quantum-device-platform.html]
June 22, 2023
Another conference prize for our group!!
Congratulations to Anna Cecilie Åsland for winning the `best poster' prize at the TNNN meeting in Åsgårdstrand.
[photo credits: Dionna Ghalambor & Knut Aasmundtveit]
June 16, 2023
Congratulations to Håkon Røst for bringing a Peder Sather grant to our group for developing our collaboration with UC-Berkeley; Specifically with the group of Prof. Frances Hellman, and in collaboration with Prof. Chris Palmstrøm at UCSB.
We look forward to developing this project and spending more time working more closely with each other.
Apr. 28, 2023
Our latest paper is now available online in ACS Applied Materials and Interfaces. Thanks for my group members, and the Ezequiel, Paolo and Silvano (at ELETTRA) for their input!
"Probing the Atomic Arrangement of Subsurface Dopants in a Silicon Quantum Device Platform"
Feb. 28 - March 6, 2023
Håkon, Anna-Cecilie, Simon, Jill Miwa and myself had beamtime at FlexPES studying delta-doping in silicon (amongst other things). Thanks to Alexei and the group at FlexPES for the discussion and support, and thanks for the group at Bloch for hosting the group strategy meeting!
January 15-19, 2023
Most of the group are at PCSI-48 and the AVS Quantum Science Workshop, hosted by Chris Palmstrøm. Between us we have 4 posters and 4 talks on a wide range of topics. We are also enjoying the Californian winter!
November 30 - December 2, 2022
We had the kick-off meeting of our "Research School for Training the Next Generation of Micro-and Nanotechnology Researchers in Norway (TNNN)"
Congratulations to Simon for winning the logo prize, and Håkon for winning "best poster".
From now on, TNNN meetings will be held annually and probably in June. The next one will be hosted by USN in Horten in June 2023.
September 16, 2022
Today we celebrate the completion of Håkon's Ph.D.! Thanks to James O'Shea , Liv Hornekær and Dennis Meier for their role in the evaluation. Thanks for all to co-authors and collaborators involved in Håkon's thesis work. Thanks to Simon Cooil and Lars Thomsen for co-supervision: But mostly, thanks to Håkon for doing such a good job!
September 5, 2022
Congratulations to Simon for getting his own FRIPRO project from the research council! The competition was especially tough this year with only 3% success rate for this call in `Banebrytende forskning' (transl. `Groundbreaking research'). Simon's project is called "Diamond and Gallium Oxide Interfaces for Power Electronics Devices (DOPED)" and will run for the next 4 years.
June , 2022
Congratulations to Anna Cecile and Håkon for winning the best talk and best poster prizes at the QuSpin annual meeting in Trondheim!
May 2, 2022
We (Amanda, Ingvild, Simon and me) completed a successful beamtime at the FLEXPES endstation (and a reunion of the MAX Brewers Guild) at MAX IV! Many thanks for Alexei, Alexander and all the support staff at MAX.
February 18, 2022
Congratulations to Simon, Ben and everyone involved in preparing our latest paper on diamond surfaces:
"The Diamond (111) Surface Reconstruction and Epitaxial Graphene Interface"
The paper is available on ArXiV and will appear in PRB very soon!
February 1, 2022
A paper draft based on our new collaboration with Damir and Smagul at IFE on CeO2 is available on ChemrXiv:
"Enhanced Hydrophobicity of CeO2 Thin Films by Surface Engineering"
September 28, 2021
After 15 months of delays (due to COVID), we finally managed to get to Trieste for synchrotron beamtime! The roadtrip is 2600km each way, but with quite some scenery. The project involves X-ray Photoelectron Diffraction at the SuperESCA beamline of Elettra. [Pics: left; Frode checking the sample temperature, right; Grossglockner, Austria (3798m). Photos by Håkon and Anna Cecilie].
September 18, 2021
Our paper on electron magnon coupling, in collaboration with Asle Sudbø and Kristian Mæland is being published in PRB:
"Electron-magnon coupling and quasiparticle lifetimes on the surface of a topological insulator"
August 1, 2021
I have now terminated my position at NTNU, and commenced at UiO instead. Here is the last group photo from me and my group at NTNU:
[Back row, L to R: Anna Cecilie, Matthias (co supervised), Simon, Jinbang. Middle row, Håkon, Øyvind, Alv. Front row, Justin, Frode and Gunvor. Photo by Amanda Langørgen]
July 30, 2021
Our latest paper on the growth and patterning of graphene is now published:
"A Simplified Method for Patterning Graphene on Dielectric Layers"
Thanks to all of our collaborators for making this happen!
April 30, 2021
The installation of our new high temperature heating chamber is now complete. Many thanks to the mechanical workshop at Aarhus University for the welding, and to the mechanical workshop at NTNU for the rest of the fabrication. Of course; thanks too to everyone in my group who helped!
April 19, 2021
Our work on "Electronic and structural properties of the natural dyes curcumin, bixin and indigo" is now published in RSC Advances.
Thanks especially to our collaborators in Brazil, and our former student Annika for making this happen!
February 9, 2021
Our work on "Low-Temperature Growth of Graphene on a Semiconductor" is now published in J. Phys. Chem. C.
Thanks especially to Håkon Røst who co-ordinated this.
1st February 2021
Our collaborative work on helium scattering has now been published. Thanks mostly to Prof. Bodil Holst (UiB) for making this happen.
"Material properties particularly suited to be measured with helium scattering..."
14th November 2020
Latest results on hBN from the nanoESCA. Thanks for Branson (Sintef, Oslo) for exfoliating the hBN flake onto the surface for us.
1st September 2020
Anna Cecilie Åsland joins our group as Ph.D. student.
After visiting in 2019/2020 and completing his Ph.D in the summer, Dr. Hu Jinbang rejoins our group as PostDoc for the next 3 years.
Welcome both!
1st August 2020
I am now appointed as Adjunct Prof. in the Semiconductor Physics group at the Department of Physics at the University of Oslo.
16th June 2020
Congratulations to our postdoc Nina, who published a new article today
(containing XPS from our lab, but otherwise based on work from her previous position in biophysics).
1st June 2020
Our latest work is published in `Quantum Materials'. Thanks to everyone involved in this collaboration.
"The sub-band structure of atomically sharp dopant profiles in silicon"
26th March 2020
One more paper published, and our first ever cover! Once again, this is in collaboration with the group of Prof. Song in Shanghai
Direct Synthesis of Semimetal Phthalocyanines on Surface with Insights Into Interfacial Properties
The Journal of Physical Chemistry C, https://doi.org/10.1021/acs.jpcc.0c00895
10th March 2020
Due to all the construction and testing with our new spin-nanoesca, I've fallen behind with updating our publications.
Here are three from 2020:
Observation and origin of the Delta manifold in Si:P delta-layers
PRB 12:121402 (05/03/2020), collaborators include Ann-Julie, Philip and Jill from Aarhus.
Ullmann coupling of 2, 7-dibromopyrene on Au (111) assisted by surface adatoms
Applied Surface Science, 513:145797 (20/02/2020), in collaboration with Prof. Song's group in Shanghai.
The occupied electronic structure of ultrathin boron doped diamond
Nanoscale Advances, DOI: 10.1039/C9NA00593E (24/02/2020), collaborators include Alex and Richard from the Diamond Electronics Group in London.
6th March 2020
First spin-resolved ARPES data from the spin-filtered NanoEsca!
[Sample is Bi(111), and the two greyscale images are the raw signal at the two working points of the spin filter. The right hand panel is the difference. The energy is just below the Fermi energy.]
14th February 2020
Rajesh looking worried whilst supervising the removal of the Phoibos from the old STM chamber
Fixing the iris mechanism, removing zinc and recoating with aerodag
Mounting the phoibos on our new prep/XPS chamber
6th February 2020
Last day of installation
First spin resolved images after installation
Final discussions after signing the acceptance documents
1st February 2020
First preparation and transfer of a sample (Ag(111)) for the NanoEsca
Young Frode is happy with the first ARPES acquisition!
17th January 2020
Coupling of the new NanoESCA with our homemade prep chamber
(and a champagne celebration moment!)
20th December 2019
First UHV in the XPS/ARPES/Preparation Chamber!
18th December 2019
Delivery of the NanoEsca, and successful manoeuvring into the lab!
5th December 2019
Today we did the first pumping and baking of our new XPS/ARPES/Preparation instrument!
27th November 2019
The first spin-resolved signal from our new spin-PEEM which is under construction by Focus and Scienta-Omicron!
Thanks to everyone who has worked hard on this project.
19th November 2019
Our latest work on silicon delta layers is now available on ArXiv:
Observation and origin of the Δ-manifold in Si:P δ-layers
1st November 2019
Dr. Rajesh Chellappan has started work as our Lab Manager
11th September 2019
Thanks to Timini and all the present and former nanostudents for my great honour!
[The thing in the frame is a silicon wafer, and the writing is pure gold]
1st July 2019
Our latest manuscript: "The occupied electronic structure of ultrathin boron doped diamond" is now on ArXiv
Thanks to all the co-authors for their work on this!
11th June 2019
As part of our ongoing collaboration with Prof. Song and the Chinese Academy of Science,
we welcome Jinbang Hu to the group as a visiting student for ~6 months.
6th May 2019
The new paper from the collaboration with Jinbang and Prof. Song's group is now published!
"Structural transformation of 2, 7‐dibromopyrene on Au (111) mediated by halogen‐bonding motifs"
24th April 2019
Our latest work on silicon delta-layers is now available on ArXiv
"The Sub-band Structure of Atomically Sharp Dopant Profiles in Silicon"
15th February 2019
Signed the contract for our new spin resolved and spatially resolved momentum microscope in Uppsala.
Delivery is preliminarily scheduled for the end of 2019
25th January 2019
Our latest work on topological metals has been published in PRB:
"Strong-coupling charge density wave in a one-dimensional topological metal"
15th November 2018
Our latest work on electron phonon interactions has been accepted in PRB:
"Phonon-induced linewidths of graphene electronic states"
(ArXiv link)
1st September 2018
We welcome our new Ph.D. student, Håkon Røst, to the group!
26th August 2018
Our latest work on electron phonon interactions is now available as a preprint on ArXiv
"Phonon-induced linewidths of graphene electronic states"
https://arxiv.org/abs/1808.08620
24th August 2018
Our latest work in collaboration woth Prof. Fei Song (Chinese Academy of Science and Shanghai Synchrotron) has been published by ACS:
J. Phys. Chem. C, Just Accepted Manuscript, DOI: 10.1021/acs.jpcc.8b06789
30th March 2018
Our latest work on chemotherapy drugs has been published:
Degradation of the chemotherapy drug 5-fluorouracil on medical-grade silver surfaces
(Applied Surface Science 435, 1213-1219)
26th January 2018
Our latest work on silicon delta layers (together with Jill Miwa's group, and others) is published:
Physical Review Letters 120 (4), 046403
11th January 2018
Our work with Thomas Jung's group on self assembled quantum dots is publishes:
Adsorbate-Induced Modification of the Confining Barriers in a Quantum Box Array
27th November 2017
Our latest work on surface interaction of chemotherapy drugs has been published in Applied Surface Science
"Degradation of the chemotherapy drug 5-fluorouracil on medical-grade silver surfaces"
and
Our work jointly with the group of PDC King (St. Andrews) has been published in Nature Materials:
Thanks to everyone who contributed to these articles!
11th October 2017
Our latest work "Accelerated ageing of molybdenum oxide" has been accepted for publication in the IOP journal, Material Research Express:
http://iopscience.iop.org/article/10.1088/2053-1591/aa9287
2nd October 2017
Frode Strand joins our group (and the QuSpin center) as Ph.D. student.
29th August 2017
Snorre's summer work has turned into an article! Using the MiBots at NanoLab to demonstrate some novel 4-point probe measurements...
23rd August 2017
Our work on UV damage to biomolecules (relevant to skin cancer) has been accepted by the ACS journal "Langmuir"
"Tautomerisation of thymine using ultraviolet light" Langmuir, 2017, 33 (38), pp 9666–9672 (2017)
18th July 2017
Our newest paper (and first paper for Marina as first author) is now available:
4th April 2017
We welcome new PostDoc Rajesh Chellappan to the group to work on graphene based devices for radiation sensing ("GraSeRad", collaboration with Sintef)
15th March 2017
Today our Center of Excellence (Norwegian: Sentre for Fremragende Forskning, SFF) was funded!
Myself, Jacob Linder, Asle Sudbø, Rembert Duine and Mathias Kläui are the PIs and Arne Brataas is the director.
The Center is called the "Center for Low Dissipation Quantum Spintronics (QuSpin)" and you can read about it here:
http://www.forskningsradet.no/no/Nyheter/Ti_nye_sentre_for_fremragende_forskning/1254025392105 and
http://www.adressa.no/nyheter/trondheim/2017/03/15/To-nye-prestisjesentre-til-Trondheim-14444623.ece
January/February 2017:
We had a very busy and productive two months!
-- We welcome Dr. Alex Schenk to the group to be our new postdoc!
-- We have a new funded project from the research council, jointly with University of Oslo:
"Non-parabolic Effects Applied to Thermoelectric materials (NEAT)"
-- We have 3 new papers accepted:
1. "On-surface manipulation of atom substitution between cobalt phthalocyanine and the Cu(111) substrate" (RSC Advances)
2. "Strong electron-phonon coupling in the sigma band of graphene" (Phys. Rev. B)
3. "In Situ Patterning of Ultrasharp Dopant Profiles in Silicon" (ACS Nano)
-- We have a "new" lab!! It is based on a 1983 ESCALAB instrument originally called "Nasjonalt Laboratorium for Overflatestudier (NALOS)", which we are repairing and upgrading. It will be reincarnated as "Ny-NALOS", and offer XPS, LEED, AES, UPS and IPES.
10th November 2016:
Our article "Thermal migration of alloying agents in aluminium" has now been accepted in MRX
10th September 2016:
Open day in the XPS lab! At least 42 students came in to visit on a Saturday...!
9th September 2016:
Our lab gets a visit from the Kavli prize winners, Christoph Gerber, Calvin Quate and Gerd Binnig (who also received the Nobel Prize).
(Photograph by Marina).
10th August 2016:
A young scientist (6 days old) visiting the lab! and learning XPS from Marina
2nd June 2016:
Federico wins the faculty prize for "best Ph.D. in natural sciences" -- congratulations Federico!!
Vice Dean Tor Grande presenting Federico with the prize, (Photo: Per Henning/NTNU).
23rd May 2016:
Our latest paper (in collaboration with PDC King and others) is now published in Nature Comms.
"Spin–valley locking in the normal state of a transition-metal dichalcogenide superconductor"
http://www.nature.com/ncomms/2016/160523/ncomms11711/full/ncomms11711.html
22nd April 2016:
Congratulations Federico!
Federico successfully defended his Ph.D thesis today.
Thanks also to Kai Rossnagel and Chris Pakes for visiting and acting as opponents.
20th March 2016:
I plan to offer two student summer jobs:
16th March 2016:
Our latest collaborative paper with Prof. King and colleagues is now availble on ArXiv:
"Spin-valley locking in the normal state of a transition-metal dichalocogenide superconductor"
http://arxiv.org/abs/1603.05207
20th November 2015:
My editorial in NanoMedicine just came online:
"Avoiding degradation of chemotherapy drugs: is graphene the answer?"
Nanomedicine, Vol. 10, No. 22 , Pages 3307-3310 (doi: 10.2217/nnm.15.142)
11th November 2015:
We have two new articles in Applied Physics Letters:
1. "Controlling the growth of epitaxial graphene on metalized diamond (111) surface"
S. P. Cooil, et al., Appl. Phys. Lett. 107, 181603 (2015); http://dx.doi.org/10.1063/1.4935073
2. "Resonant photoemission spectroscopy for intermediate band materials"
F. Mazzola, et al., Appl. Phys. Lett. 107, 192104 (2015); http://dx.doi.org/10.1063/1.4935536
10th October 2015:
We have contributed to Teknisk Ukeblad's article on CQC2T's Quantum Computing breakthrough!
(TU's article) KVANTEDATAMASKINER: Så viktig er gjennombruddet i kvantedatamaskiner
(Original Nature article) A two-qubit logic gate in silicon
29th September 2015:
Our latest paper just appeared online. Thanks to Phil King and his group for the ongoing collaboration!
2nd September 2015:
We are currently offering a fully funded Ph.D. position:
http://www.jobbnorge.no/ledige-stillinger/stilling/117024/phd-position-in-experimental-physics
http://brightrecruits.com/job/7935/phd-position-in-experimental-physics
3rd August 2015:
Our latest work "Hierarchical spin-orbital polarisation of a giant Rashba system"
is available on ArXiv: http://arxiv.org/abs/1507.08588
8th June 2015:
We have some attention in the news!
"Supermaterialet grafén kan gi bedre kreftbehandling" Gemini
"Catheter studies raise acid alert" Nanotechweb
"Improving the delivery of chemotherapy with graphene" Institute of Physics
10th April 2015:
Good news comes all at once - over the Easter break, we have had 4 articles accepted:
1. "Graphene coatings for chemotherapy; Avoiding silver-mediated degradation" in the IOPs new journal 2D materials
2. "Tunable High Aspect Ratio Polymer Nanostructures for Cell Interfaces" in RSC's journal Nanoscale
3. "One-dimensional spin texture of Bi(441): Quantum spin Hall properties" in APS's journal Physical Review B.
4. "Low-temperature Growth of Bismuth Thin Films with (111) Facet on Highly Oriented Pyrolytic Graphite" in ACS's journal Applied Materials & Interfaces.
-- I'll post links to the articles once they are available online. As always, these articles involve multiple collaborations, so thanks and congratulations to those involved!
24th September 2014
Our article on the confinement of delta-layers has just been accepted in ACS Nano:
http://pubs.acs.org/doi/abs/10.1021/nn5045239
22nd August 2014
A PostDoc position is now available in my group:
21st August 2014
Our project on WSe2, jointly with Prof. Phil King, has been accepted by Nature Physics.
A preview is available on ArXiv: http://arxiv.org/abs/1408.6778
(more details and a link will follow soon).
28th July 2014
Teknisk Ukeblad have written an article about our research work:
KVANTEDATAMASKINER: NTNU-forskere vil bruke silisium til kvantedatabehandling
30th June 2014
We were interviewed by 'Teknisk Ukeblad' about the D-Wave quantum computer:
D-WAVE: Er det så vanskelig å bevise at kvantedata fungerer?
2nd May 2014
Our APL is now online! thanks to everyone involved.
http://scitation.aip.org/content/aip/journal/apl/104/17/10.1063/1.4874651
29th April 2014
Our manuscript "Disentangling phonon and impurity interactions in delta-doped Si(001)" has just been accepted for publication in Applied Physics Letters!... I'll post a link as soon as it is available online.
5th March 2014
Our Nano Letters is now online!
[figure: copyright held by American Chemical Society (2014)]
26th February 2014
Our manuscript "Valley splitting in a silicon quantum device platform" has been accepted by Nano Letters!
"just accepted" manuscript available here
Thanks to the co-authors for their hard work.
12th February 2014
Elise Østli joins our group as M.Sc. Student (co-supervised by Prof. Aune).
Her project is on XPS analysis of chemotherapy drugs.
15th January 2014
Cecilie Granerød joins our group as M.Sc. Student!
project title: "Measuring spin-orbit interactions in novel 2D materials"
30th November 2013
Federico's PRL is now published - http://prl.aps.org/abstract/PRL/v111/i21/e216806
5th November 2013
Our manuscript "Electron-phonon coupling-induced kinks in the sigma band of graphene"
is now accepted in PRL!! - congratulations Federico :-)
(an early draft is available on ArXiv; http://arxiv.org/abs/1305.6210)
4th June 2013
Our draft "Electron-phonon coupling-induced kinks in the sigma band of graphene" has been uploaded to arXiv:
http://arxiv.org/abs/1305.6210
31st May 2013
Our article "Exploring the limits of n-type ultra-shallow junction formation", is now available online.
http://pubs.acs.org/doi/abs/10.1021/nn4016407
22nd May 2013
Our article "Exploring the limits of n-type ultra-shallow junction formation", submitted to ACS Nano, has just been accepted.
- well done Craig!
13th May 2013
Our work got noticed by Nature Nanotechnology; see their Research Highlight here:
...and NTNU's announcement of it here:
29th March 2013
Our article "Excitation of Coherent Phonons in the One-Dimensional Bi(114) Surface" is now available
Phys. Rev. Lett. 110, 136806 (2013), http://prl.aps.org/abstract/PRL/v110/i13/e136806
27th March 2013
Our article "Direct Measurement of the Band Structure of a Buried Two-Dimensional Electron Gas" is now available
Phys. Rev. Lett. 110, 136801 (2013), http://prl.aps.org/abstract/PRL/v110/i13/e136801
20th March 2013
Another article has been accepted in PRL - the second this year!!
"Excitation of coherent phonons in the one-dimensional Bi(114) surface"
Until it appears in a printed version, you can access it on arXiv: http://arxiv.org/abs/1303.2718
5th March 2013
Our article "Surface-sensitive conductivity measurement using a micro multi-point probe approach" is now available online:
Rev. Sci. Instrum. 84, 033901 (2013)
http://rsi.aip.org/resource/1/rsinak/v84/i3/p033901_s1
19th February 2013
Our article "Hole doping of graphene supported on Ir (111) by AlBr3" is now available online:
Applied Physics Letters 102, 061601 (2013)
29th January 2013
An article based on the draft we posted on ArXiv has just been accepted by PRL!
"Direct band structure measurement of a buried two-dimensional electron gas"
December 2012:
The last new paper of 2012...
"Microscopic four-point-probe resistivity measurements of shallow, high density doping layers in silicon"
Applied Physics Letters 101 (26), 262105-262105-4
http://apl.aip.org/resource/1/applab/v101/i26/p262105_s1
August 2012:
Another of our papers available online!!
"Extracting the near surface stoichiometry of BiFe0.5Mn0.5O3 thin films; a finite element maximum entropy approach"
http://www.sciencedirect.com/science/article/pii/S0039602812002725?v=s5
July 2012:
Our paper "Robust Surface Doping of Bi2Se3 by Rb Intercalation" has been accepted by ACS Nano!
http://pubs.acs.org/doi/abs/10.1021/nn3021822
And, our paper "Iron-mediated growth of epitaxial graphene on SiC and diamond" is published in Carbon!
http://www.sciencedirect.com/science/article/pii/S0008622312005696
June 2012: I have accepted a position at the Norwegian University of Science and Technology (NTNU) as førsteamanuensis (transl. Associate Professor). I plan to start in October.
April 2012: Our article on LSMO thin films is now published!
http://www.sciencedirect.com/science/article/pii/S0039602812001501