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Dr Steven Clowes

EPSRC Advanced Research Fellow

Qualifications: MSc, PhD

Email:
Phone: Work: 01483 68 9827
Room no: 12 ATI 02

Further information

Biography

1994 BSc in Physics from University of York, UK
1995 MSc in Surface Science from Loughborough University, UK
1999 PhD in Experimental Studies of Surface-Adsorbate Interactions and Surface magnetism from University of York, UK
1999-2001 postdoctoral research associate at Rutgers University NJ, USA
2001-2007 postdoctoral research associate at Imperial College London, UK
2007 Laboratory Manager of fabrication facilities for the ATI
2007 EPSRC Advanced Research Fellow at the ATI

Research Interests

Semiconductor spintronics

Research Collaborations

Imperial College London
Cambridge University

Publications

Highlights

  • Li J, Litvinenko KL, Clowes SK, Gilbertson AM, Cohen LF. (2012) 'Observation of spin dependent photocoductivity in InSb quantum well nanowires'. AIP Applied Physics Letters, 101 (15)
    doi: 10.1063/1.4760223
    Full text is available at: http://epubs.surrey.ac.uk/735787/

    Abstract

    We report on the electrical detection of spin dependent photoconductivity in 500 nm wide InSb quantum well nanowires using the optical orientation of electron spins. By applying weak magnetic fields (≈ 200 mT), we observe a spin filtering effect of classical origin caused by spin dependent back scattering of electrons from the sidewalls. Spin dependent features in the longitudinal photovoltage decay with temperature and disappears at characteristic energy (≈ 50 K) consistent with the theoretical spin splitting and the thermal level broadening. We show that the observed signal is due to the inversion asymmetry of the quantum well, with an additional Zeeman contribution. © 2012 American Institute of Physics.

  • Nordin MN, Li J, Clowes SK, Curry RJ. (2012) 'Temperature dependent optical properties of PbS nanocrystals.'. Nanotechnology, England: 23 (27)
    doi: 10.1088/0957-4484/23/27/275701
  • Li J, Gilbertson AM, Litvinenko KL, Cohen LF, Clowes SK. (2012) 'Transverse focusing of spin-polarized photocurrents'. American Physical Society Physical Review B (Condensed Matter and Materials Physics), 85 Article number 045431
    doi: 10.1103/PhysRevB.85.045431
    Full text is available at: http://epubs.surrey.ac.uk/148877/

    Abstract

    We measure transverse magnetically focused photocurrent signals in an InSb/InAlSb quantum well device. Using optical spin orientation by modulated circularly polarized light an electron spin-dependent signal is observed due to the spin-orbit interaction. Simulations of the focusing signal are performed using a classical billiard ball model, which includes both spin precession and a spin-dependent electron energy. The simulated data suggest that a signal dependent on the helicity of the incident light is expected for a Rashba parameter α > 0.1 eVÅ and that a splitting of the focusing signal is not expected to be observed in linear polarized photocurrent and purely electrical measurements.

  • Stachel S, Olbrich P, Zoth C, Hagner U, Stangl T, Karl C, Lutz P, Bel'kov VV, Clowes SK, Ashley T, Gilbertson AM, Ganichev SD. (2012) 'Interplay of spin and orbital magnetogyrotropic photogalvanic effects in InSb/(Al,In) Sb quantum well structures'. PHYSICAL REVIEW B, 85 (4) Article number ARTN 045305
    doi: 10.1103/PhysRevB.85.045305
    Full text is available at: http://epubs.surrey.ac.uk/56945/
  • Leontiadou MA, Litvinenko KL, Gilbertson AM, Pidgeon CR, Branford WR, Cohen LF, Fearn M, Ashley T, Emeny MT, Murdin BN, Clowes SK. (2011) 'Experimental determination of the Rashba coefficient in InSb/InAlSb quantum wells at zero magnetic field and elevated temperatures'. IOP PUBLISHING LTD JOURNAL OF PHYSICS-CONDENSED MATTER, 23 (3) Article number ARTN 035801
    doi: 10.1088/0953-8984/23/3/035801
    Full text is available at: http://epubs.surrey.ac.uk/7763/
  • Litvinenko KL, Leontiadou MA, Li J, Clowes SK, Emeny MT, Ashley T, Pidgeon CR, Cohen LF, Murdin BN. (2010) 'Strong dependence of spin dynamics on the orientation of an external magnetic field for InSb and InAs'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 96 (11) Article number ARTN 111107
    doi: 10.1063/1.3337111
    Full text is available at: http://epubs.surrey.ac.uk/7724/
  • Magnus F, Clowes SK, Gilbertson AM, Branford WR, Barkhoudarov ED, Cohen LF, Singh LJ, Barber ZH, Blamire MG, Buckle PD, Buckle L, Ashley T, Eustace DA, McComb DW. (2007) 'Electrical characterization of MgO tunnel barriers grown on InAs (001) epilayers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 91 (12) Article number ARTN 122106
    doi: 10.1063/1.2784933
    Full text is available at: http://epubs.surrey.ac.uk/470/
  • Itskos G, Harbord E, Clowes SK, Clarke E, Van Dorpe P, Van Roy W, Cohen LF, Murray R. (2007) 'Oblique Hanle measurements of InAs/GaAs quantum dot spin-light emitting diodes'. AMER INST PHYSICS Physics of Semiconductors, Pts A and B, Vienna, AUSTRIA: 28th International Conference on the Physics of Semiconductors (ICPS-28) 893, pp. 1289-1290.
  • Itskos G, Harbord E, Clowes SK, Clarke E, Cohen LF, Murray R, Van Dorpe P, Van Roy W. (2006) 'Oblique Hanle measurements of InAs/GaAs quantum dot spin-light emitting diodes'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 88 (2) Article number ARTN 022113
    doi: 10.1063/1.2163074
    Full text is available at: http://epubs.surrey.ac.uk/350/

Journal articles

  • Li J, Litvinenko KL, Clowes SK, Gilbertson AM, Cohen LF. (2012) 'Observation of spin dependent photocoductivity in InSb quantum well nanowires'. AIP Applied Physics Letters, 101 (15)
    doi: 10.1063/1.4760223
    Full text is available at: http://epubs.surrey.ac.uk/735787/

    Abstract

    We report on the electrical detection of spin dependent photoconductivity in 500 nm wide InSb quantum well nanowires using the optical orientation of electron spins. By applying weak magnetic fields (≈ 200 mT), we observe a spin filtering effect of classical origin caused by spin dependent back scattering of electrons from the sidewalls. Spin dependent features in the longitudinal photovoltage decay with temperature and disappears at characteristic energy (≈ 50 K) consistent with the theoretical spin splitting and the thermal level broadening. We show that the observed signal is due to the inversion asymmetry of the quantum well, with an additional Zeeman contribution. © 2012 American Institute of Physics.

  • Nordin MN, Li J, Clowes SK, Curry RJ. (2012) 'Temperature dependent optical properties of PbS nanocrystals.'. Nanotechnology, England: 23 (27)
    doi: 10.1088/0957-4484/23/27/275701
  • Li J, Gilbertson AM, Litvinenko KL, Cohen LF, Clowes SK. (2012) 'Transverse focusing of spin-polarized photocurrents'. American Physical Society Physical Review B (Condensed Matter and Materials Physics), 85 Article number 045431
    doi: 10.1103/PhysRevB.85.045431
    Full text is available at: http://epubs.surrey.ac.uk/148877/

    Abstract

    We measure transverse magnetically focused photocurrent signals in an InSb/InAlSb quantum well device. Using optical spin orientation by modulated circularly polarized light an electron spin-dependent signal is observed due to the spin-orbit interaction. Simulations of the focusing signal are performed using a classical billiard ball model, which includes both spin precession and a spin-dependent electron energy. The simulated data suggest that a signal dependent on the helicity of the incident light is expected for a Rashba parameter α > 0.1 eVÅ and that a splitting of the focusing signal is not expected to be observed in linear polarized photocurrent and purely electrical measurements.

  • Stachel S, Olbrich P, Zoth C, Hagner U, Stangl T, Karl C, Lutz P, Bel'kov VV, Clowes SK, Ashley T, Gilbertson AM, Ganichev SD. (2012) 'Interplay of spin and orbital magnetogyrotropic photogalvanic effects in InSb/(Al,In) Sb quantum well structures'. PHYSICAL REVIEW B, 85 (4) Article number ARTN 045305
    doi: 10.1103/PhysRevB.85.045305
    Full text is available at: http://epubs.surrey.ac.uk/56945/
  • Abdul Rahman AT, Bräuer-Krisch E, Brochard T, Adamovics J, Clowes SK, Bradley D, Doran SJ. (2011) 'Sophisticated test objects for the quality assurance of optical computed tomography scanners.'. Phys Med Biol, England: 56 (14), pp. 4177-4199.
    doi: 10.1088/0031-9155/56/14/001
  • Leontiadou MA, Litvinenko KL, Gilbertson AM, Pidgeon CR, Branford WR, Cohen LF, Fearn M, Ashley T, Emeny MT, Murdin BN, Clowes SK. (2011) 'Experimental determination of the Rashba coefficient in InSb/InAlSb quantum wells at zero magnetic field and elevated temperatures'. IOP PUBLISHING LTD JOURNAL OF PHYSICS-CONDENSED MATTER, 23 (3) Article number ARTN 035801
    doi: 10.1088/0953-8984/23/3/035801
    Full text is available at: http://epubs.surrey.ac.uk/7763/
  • Litvinenko KL, Leontiadou MA, Li J, Clowes SK, Emeny MT, Ashley T, Pidgeon CR, Cohen LF, Murdin BN. (2010) 'Strong dependence of spin dynamics on the orientation of an external magnetic field for InSb and InAs'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 96 (11) Article number ARTN 111107
    doi: 10.1063/1.3337111
    Full text is available at: http://epubs.surrey.ac.uk/7724/
  • Magnus F, Yates KA, Clowes SK, Miyoshi Y, Bugoslavsky Y, Cohen LF, Aziz A, Burnell G, Blamire MG, Josephs-Franks PW. (2008) 'Interface properties of Pb/InAs planar structures for Andreev spectroscopy'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 92 (1) Article number ARTN 012501
    doi: 10.1063/1.2828979
    Full text is available at: http://epubs.surrey.ac.uk/378/
  • Magnus F, Clowes SK, Gilbertson AM, Branford WR, Barkhoudarov ED, Cohen LF, Singh LJ, Barber ZH, Blamire MG, Buckle PD, Buckle L, Ashley T, Eustace DA, McComb DW. (2007) 'Electrical characterization of MgO tunnel barriers grown on InAs (001) epilayers'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 91 (12) Article number ARTN 122106
    doi: 10.1063/1.2784933
    Full text is available at: http://epubs.surrey.ac.uk/470/
  • Singh LJ, Oliver RA, Barber ZH, Eustace DA, McComb DW, Clowes SK, Gilbertson AM, Magnus F, Branford WR, Cohen LF, Buckle L, Buckle PD, Ashley T. (2007) 'Preparation of InAs(001) surface for spin injection via a chemical route'. IOP PUBLISHING LTD JOURNAL OF PHYSICS D-APPLIED PHYSICS, 40 (10), pp. 3190-3193.
    doi: 10.1088/0022-3727/40/10/024
  • Branford WR, Singh LJ, Barber ZH, Kohn A, Petford-Long AK, Van Roy W, Magnus F, Morrison K, Clowes SK, Bugoslavsky YV, Cohen LF. (2007) 'Temperature insensitivity of the spin-polarization in Co2MnSi films on GaAs (001)'. IOP PUBLISHING LTD NEW JOURNAL OF PHYSICS, 9 Article number PII S1367-2630(07)34448-0
    doi: 10.1088/1367-2630/9/2/042
    Full text is available at: http://epubs.surrey.ac.uk/124/
  • Zhang T, Harris JJ, Branford WR, Clowes SK, Cohen LF, Solin SA. (2006) 'Exploration of the inherent magnetoresistance in InSb thin films'. IOP PUBLISHING LTD SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 21 (12), pp. 1543-1546.
    doi: 10.1088/0268-1242/21/12/007
  • Litvinenko KL, Murdin BN, Allam J, Pidgeon CR, Bird M, Morris K, Branford W, Clowes SK, Cohen LF, Ashley T, Buckle L. (2006) 'Spin relaxation in n-InSb/AlInSb quantum wells'. IOP PUBLISHING LTD NEW JOURNAL OF PHYSICS, 8 Article number PII S1367-2630(06)15617-7
    doi: 10.1088/1367-2630/8/4/049
  • Itskos G, Harbord E, Clowes SK, Clarke E, Cohen LF, Murray R, Van Dorpe P, Van Roy W. (2006) 'Oblique Hanle measurements of InAs/GaAs quantum dot spin-light emitting diodes'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 88 (2) Article number ARTN 022113
    doi: 10.1063/1.2163074
    Full text is available at: http://epubs.surrey.ac.uk/350/
  • Zhang T, Harris JJ, Branford WR, Bugoslavsky YV, Clowes SK, Cohen LF, Husmann A, Solin SA. (2006) 'Tuning the inherent magnetoresistance of InSb thin films'. AMER INST PHYSICS APPLIED PHYSICS LETTERS, 88 (1) Article number ARTN 012110
    doi: 10.1063/1.2162666
    Full text is available at: http://epubs.surrey.ac.uk/454/
  • Zhang T, Harris JJ, Clowes SK, Debnath M, Bennett A, Cohen LF, Lyford T, Fewster PF. (2005) 'Evidence for dislocation-related amphoteric behaviour of Si dopant in high-mobility InSb thin films'. IOP PUBLISHING LTD SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 20 (12), pp. 1153-1156.
    doi: 10.1088/0268-1242/20/12/001

Conference papers

  • Leontiadou MA, Litvinenko KL, Clowes SK, Springholz G, Schwarzl T, Eibelhuber M, Heiss W, Pidgeon CR, Murdin BN. (2011) 'Substantial temperature dependence of transverse electron g*-factor in lead chalcogenide multi-quantum wells'. American Institute of Physics AIP Conference Proceedings, Blacksburg, USA: 15TH INTERNATIONAL CONFERENCE ON NARROW GAP SYSTEMS 1416, pp. 178-180.
    doi: 10.1063/1.3671728
  • Litvinenko K, Leontiadou M, Li J, Bowyer E, Clowes S, Pidgeon CR, Murdin B. (2011) 'Manipulation of spin dynamics in semiconductor structures by orientation of small external magnetic field'. American Institute of Physics AIP Conference Proceedings, Seoul, South Korea: ICPS2010, 30th International Conference on the Physics of Semiconductors 1399, pp. 657-658.
    doi: 10.1063/1.3666548
  • Yahya I, Mustaza SM, Yahya I, Stolojan V, Clowes S, Silva SRP. (2010) 'Carbon nanotube field effect transistor measurements in vacuum'. IEEE International Conference on Semiconductor Electronics, Proceedings, ICSE, , pp. 224-228.
    doi: 10.1109/SMELEC.2010.5549562
  • Branford WR, Gilbertson AM, Buckle PD, Buckle L, Ashley T, Magnus F, Clowes SK, Harris JJ, Cohen LF. (2008) 'Gate dependence of spin-splitting in an InSb/InAlSb quantum well'. SPRINGER NARROW GAP SEMICONDUCTORS 2007, Guildford, ENGLAND: 13th International Conference on Narrow Gap Semiconductors 119, pp. 3-5.
  • Litvinenko KL, Murdin BN, Clowes SK, Nikzad L, Allam J, Pidgeon CR, Branford W, Cohen LF, Ashley T, Buckle L. (2008) 'Density and well-width dependence of the spin relaxation in n-InSb/AlInSb quantum wells'. SPRINGER NARROW GAP SEMICONDUCTORS 2007, Guildford, ENGLAND: 13th International Conference on Narrow Gap Semiconductors 119, pp. 19-21.
  • Eustace DA, McComb DW, Buckle L, Buckle P, Ashley T, Singh LJ, Barber ZH, Gilbertson AM, Branford WR, Clowes SK, Cohen LF. (2008) '(S)TEM Characterisation of InAs/MgO/Co Multilayers'. SPRINGER-VERLAG BERLIN MICROSCOPY OF SEMICONDUCTING MATERIALS 2007, Univ Cambridge, Cambridge, ENGLAND: 15th Conference on Microscopy of Semiconducting Materials 120, pp. 153-156.
  • Magnus F, Burnell G, Miyoshi Y, Yates KA, Bugoslavsky Y, Clowes SK, Josephs-Franks PW, Blamire MG, Cohen LF. (2007) 'Planar Andreev spectroscopy in InAs'. AMER INST PHYSICS Physics of Semiconductors, Pts A and B, Vienna, AUSTRIA: 28th International Conference on the Physics of Semiconductors (ICPS-28) 893, pp. 1281-1282.
  • Itskos G, Harbord E, Clowes SK, Clarke E, Van Dorpe P, Van Roy W, Cohen LF, Murray R. (2007) 'Oblique Hanle measurements of InAs/GaAs quantum dot spin-light emitting diodes'. AMER INST PHYSICS Physics of Semiconductors, Pts A and B, Vienna, AUSTRIA: 28th International Conference on the Physics of Semiconductors (ICPS-28) 893, pp. 1289-1290.
  • Zhang T, Harris JJ, Branford WR, Clowes SK, Cohen LF, Solin SA. (2007) 'Inherent magnetoresistance and surface morphology of InSb thin films'. AMER INST PHYSICS Physics of Semiconductors, Pts A and B, Vienna, AUSTRIA: 28th International Conference on the Physics of Semiconductors (ICPS-28) 893, pp. 561-562.
  • Clowes SK, Branford WR, Gilbertson AM, Zhang T, Buckle L, Husmann A, Solin SA, Cohen LF. (2007) 'Improved geometric control of the high-field linear magnetoresistance by metallic bridges in InSb arrays'. AMER INST PHYSICS Physics of Semiconductors, Pts A and B, Vienna, AUSTRIA: 28th International Conference on the Physics of Semiconductors (ICPS-28) 893, pp. 1383-1384.

Books

  • Murdin BN, Clowes SK. (2008) Narrow gap semiconductors 2007. Springer

Teaching

Level 2 Modern Physics / Atomic Physics component
Second year laboratory

Departmental Duties

Academic in charge of cleanroom facilities.