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Prof. Dr. Thomas Lorenz

Contact

Phone : +49-221-470-3593

Fax:      +49-221-470-6708

Room:    223

e-mail:   lorenz@ph2.uni-koeln.de

Research

  • thermodynamic and transport propoerties of correlated electron systems
  • low dimensional magnetism and quantum spin systems
  • (unconventional) superconductors
  • interplay of charge, spin, lattice and orbital degrees of freedom
  • transiton metal oxides
  • single crystal growth

Scientific career

Apl. Professor:

May 2015, University of Cologne

Habilitation:

January 2010, University of Cologne

Anomalous Behavior of Spin Liquids: Thermodynamics and Heat Transport

Post-Doc:

October 1999 until September 2002: Scientific Assistant at the Institute of Physics II,  University of Cologne

October 1998 until September 1999: Post-Doc in the Oxide Spin Electronic Network (OXSEN) at the Laboratoire de l'Etat Solide and the Institut d'Electronique Fondamentale, Universite Paris-Sud, France. Research field: single crystal growth and studies of the magnetotransport properties of doped rare earth manganites and cobaltates.

PhD:

July 1998, University of Cologne

Thesis: Thermodynamische Eigenschaften des Spin-Peierls-Systems CuGeO3 (ISBN 3-8265-4179-0)

Referees: Prof. Dr. R. Gross, Prof. Dr. A. Freimuth & Prof. Dr. A Klümper

 

Diploma:

July 1994, University of Cologne

Thesis: Aufbau eines Magnetkryostaten und Messungen der thermischen Ausdehnung von La1.87Sr0.13CuO4 im transversalen Magnetfeld

Referees: Prof. Dr. H. Micklitz, Prof. Dr. E. Müller-Hartmann

University studies:

1990-1994 University of Cologne, Germany

1989-1990 University of Vienna, Austria

1987-1989 University of Freiburg, Germany

Publications

2017

  • Carl Rischau, Xiao Lin, Christoph Grams, Dennis Finck, Steffen Harms, Johannes Engelmayer, Thomas Lorenz, Yann Gallais, Benoit Fauqué, Joachim Hemberger and Kamran Behnia
    A ferroelectric quantum phase transition inside the superconducting dome of Sr1-xCaxTiO3-δ
    Nature Physics, 4085, (2017), http://www.nature.com/articles/nphys4085.epdf
  • Oliver Breunig, Markus Garst, Andreas Klümper, Jens Rohrkamp, Mark M. Turnbull and Thomas Lorenz
    Quantum criticality in the spin-1/2 Heisenberg chain system copper pyrazine dinitrate
    Submitted, Sci Adv, (2017). arXiv:1709.00274 [PDF, 2146 kB]
  • S. Kunkemöller, D. Brüning, A. Stunault, A.A. Nugroho, T. Lorenz and M. Braden
    Magnetic shape-memory effect in SrRuO$_3$
    Submitted, Phys. Rev. Lett., (2017). arXiv:1709.05688 [PDF, 5064 kB]

2016

  • S. Holbein, M. Ackermann, L. Chapon, P. Steffens, A. Gukasov, A. Sazonov, O. Breunig, Y. Sanders, P. Becker, L. Bohaty, T. Lorenz and M. Braden
    Strong magnetoelastic coupling at the transition from harmonic to anharmonic order in NaFe(WO4)2 with 3d5 configuration
    Phys. Rev. B, 94, 104423, (2016). arXiv:1609.01849 [PDF, 4648 kB]

2015

2014

2013

2012

  • A C. Komarek, M. Reuther, T. Lorenz, A. Cousson, P. Link, W. Morgenroth, D. Trots, C. Baehtz and M. Braden
    Evidence for charge and orbital order in the doped titanates RE(1-x)CaxTiO3 (RE=Y, Er, Lu)
    Submitted, Phys. Rev. Lett., (2012). arXiv:1109.0234
  • G. Kolland, O. Breunig, M. Valldor, M. Hiertz, J. Frielingsdorf and T. Lorenz
    Thermal conductivity and specific heat of the spin-ice compound Dy2 Ti2 O7 : Experimental evidence for monopole heat transport
    Phys. Rev. B, 86, 060402(R), (2012). arXiv:1205.5700 [PDF, 358 kB]
  • Z. Hu, Hua Wu, T.C. Koethe, S.N. Barilo, S.V. Shiryaev, G.L. Bychkov, C. Schüßler-Langeheine, T. Lorenz, A. Tanaka, H.H. Hsieh, H-J. Lin, C.T. Chen, N.B. Brookes, S. Agrestini, Y-Y. Chin, M. Rotter and L.H. Tjeng
    Spin-state order/disorder and metal insulator transition in GdBaCo$_2$O$_{5.5}$: experimental determination of the underlying electronic structure
    New J. Phys., 14, 123025, (2012)

2011

  • G. Giovannetti, A. Stroppa, S. Picozzi, D. Baldomir, V. Pardo, S. Blanco-Canosa, F. Rivadulla, S. Jodlauk, D. Niermann, J. Rohrkamp, T. Lorenz , S. Streltsov, D.I. Khomskii and J. Hemberger
    Dielectric properties and magnetostriction of the collinear multiferroic spinel CdV2O4
    Phys. Rev. B, 83, 060402(R), (2011)
  • M. Valldor, O. Heyer, A. C. Komarek, A. Senyshyn, M. Braden and T. Lorenz
    Magnetostrictive Neel ordering of the spin-5/2 ladder compound BaMn2O3: Distortion-induced lifting of geometrical frustration
    Phys. Rev. B, 83, 024418, (2011). arXiv:1010.1183 [PDF, 897 kB]
  • S.K.Niesen, O. Heyer, T. Lorenz and M. Valldor
    Antiferromagnetic Heisenberg S=5/2 spin chain compound SrMn2V2O8
    J. Magn. Magn. Mater., 323, 2575, (2011). arXiv:1103.1830
  • N. Hollmann, M. W. Haverkort, M. Benomar, M. Cwik, M. Braden and T. Lorenz
    Evidence for a temperature-induced spin-state transition of Co3+ in La2-xSrxCoO4
    Phys. Rev. B, 83, 174435, (2011). arXiv:1204.0730 [PDF, 377 kB]
  • A. C. Komarek, M. Isobe, J. Hemberger, D. Meier, T. Lorenz, D. Trots, A. Cervellino, M. T. Fernández-Díaz, Y. Ueda and M. Braden
    Dimerization and Charge Order in Hollandite K2V8O16
    Phys. Rev. Lett., 107, 027201, (2011)
  • M. K. Forthaus, G. R. Hearne, N. Manyala, O. Heyer, R. A. Brand, D. I. Khomskii, T. Lorenz and M. M. Abd-Elmeguid
    Pressure-induced quantum phase transition in Fe1−xCoxSi (x = 0.1,0.2)
    Phys. Rev. B, 83, 085101, (2011) [PDF, 1294 kB]
  • O. Heyer, T. Lorenz, V. B. Zabolotnyy, D. V. Evtushinsky, S. V. Borisenko, I. Morozov, L. Harnagea, S. Wurmehl, C. Hess and B. Büchner
    Resistivity and Hall effect of LiFeAs: Evidence for electron-electron scattering
    Phys. Rev. B, 84, 064512, (2011). arXiv:1010.2876 [PDF, 355 kB]
  • O. Heyer, P. Link, D. Wandner, U Ruschewitz and T. Lorenz
    Thermodynamic properties and resistivity of the ferromagnetic semiconductor EuC2
    New J. Phys., 13, 113041, (2011). arXiv:1103.0980 [PDF, 752 kB]
  • A.V. Kalinov, O.Yu. Gorbenko, A.N. Taldenkov, J. Rohrkamp, O. Heyer, S. Jodlauk, N.A. Babushkina, L.M. Fisher, A.R. Kaul, D.I. Khomskii, K.I. Kugel and T. Lorenz
    Phase Diagram of Spin States and Magnetic Interactions in Isotope Substituted (Pr,Eu)0.7Ca0.3CoO3
    Solid State Phenomena, 168-169, 465, (2011) [PDF, 215 kB]

2010

  • H. Banks, N. J. Hillier, J. S. Schilling, J. Rohrkamp, T. Lorenz, J. A. Mydosh, T. Fickenscher and R. Pöttgen
    Dependence of the magnetic ordering temperature on hydrostatic pressure for the ternary intermetallic compounds GdAgMg, GdAuMg, EuAgMg, and EuAuMg
    Phys. Rev. B, 81, 212403, (2010) [PDF, 388 kB]
  • A. V. Kalinov, O. Yu. Gorbenko, A. N. Taldenkov, J. Rohrkamp, O. Heyer, S. Jodlauk, N. A. Babushkina, L. M. Fisher, A. R. Kaul, A. A. Kamenev, T. G. Kuzmova, D. I. Khomskii, K. I. Kugel and T. Lorenz
    Phase diagram and isotope effect in (Pr1−yEuy)0.7Ca0.3CoO3 cobaltites exhibiting spin-state transitions
    Phys. Rev. B, 81, 134427, (2010). arXiv:0909.2978 [PDF, 891 kB]
  • Sina Zimmermann, Matthias Brühmann, Frederick Casper, Oliver Heyer, Thomas Lorenz, Claudia Felser, Anja-Verena Mudring and Gerd Meyer
    Eight-Coordinate Endohedral Rhenium, Osmium and Iridium Atoms in Rare- Earth Halide Cluster Complexes
    Eur. J. Inorg. Chem., 18, 2613, (2010) [PDF, 832 kB]
  • J. Rohrkamp, M.D. Phillips, M.M. Turnbull and T. Lorenz
    Thermal expansion of the spin-1/2 Heisenberg-chain compound Cu(C4H4N2)(NO3)2
    JPCS, 200, 012169, (2010). arXiv:0907.0400 [PDF, 4985 kB]
  • N. A. Babushkina, A. N. Taldenkov, A. V. Kalinov, L. M. Fisher, O. Yu. Gorbenko, T. Lorenz, D. I. Khomskii and K. I. Kugel
    Isotope Effect and Characteristic Features of the Phase Diagram for Cobaltites with Spin State Transitions
    JETP, 111, 189, (2010) [PDF, 220 kB]
  • M. K. Forthaus, K. Sengupta, O. Heyer, N. E. Christensen, A. Svane, K. Syassen, D. I. Khomskii, T. Lorenz and M. M. Abd-Elmeguid
    Superconductivity in SnO: A Nonmagnetic Analog to Fe-Based Superconductors?
    Phys. Rev. Lett., 105, 157001, (2010). arXiv:1009.3787
  • A. Senyshyn, B. Schwarz, T. Lorenz, V. T. Adamiv, Ya. V. Burak, J. Banys, R. Grigalaitis, L. Vasylechko, H. Ehrenberg and H. Fuess
    Low-temperature crystal structure, specific heat, and dielectric properties of lithium tetraborate Li2B4O7
    J. Appl. Phys., 108, 093524, (2010) [PDF, 490 kB]

2009

2008

2007

2006

2005

2004

2003

2002

2001

1999

  • D. Bruns, B. Büchner, R. Gross, T. Lorenz and S. Uchida
    Thermal expansion of La1.85Sr0.15CuO4 in magnetic fields up to 14 Tesla
    J. Low Temp. Phys., 117, 1453, (1999)
  • T. Lorenz
    Magnetic frustration and spin-Peierls transition in CuGeO3
    B. Kramer, Advances in Solid State Physics, 39, Vieweg Verlag, Braunschweig, (1999) [PDF, 1123 kB]
  • B. Büchner, T. Lorenz, R. Walter, H. Kierspel, A. Revcolevschi and G. Dhalenne
    Spin-Peierls order parameter and antiferromagnetism in the dimerized and incommensurate phases of Zn-doped CuGeO3
    Phys. Rev. B, 59, 6886, (1999) [PDF, 425 kB]
  • B. Büchner, T. Lorenz, R. Walter, H. Kierspel, A. Revcolevschi and G. Dhalenne
    Spin-Peierls order parameter and antiferromagnetism in the dimerized and incommensurate phases of Zn-doped CuGeO3
    Phys. Rev. B, 59, 6886, (1999)

1998

  • S. Uma, W. Schnelle, E. Gmelin, G. Rangarajan, S. Skanthakumar, J.W. Lynn, R. Walter, T. Lorenz, B. Büchner and A. Erb
    Magnetic Ordering in Single Crystals of PrBa2Cu3O7-d
    J. Phys.: Condens. Matter, 10, L33, (1998) [PDF, 125 kB]
  • T. Lorenz, B. Büchner, P.H.M. van Loosdrecht, F. Schönfeld, G. Chouteau, A. Revcolevschi and G. Dhalenne
    Incommensurate phase of CuGeO3: from solitons to sinusoidal modulation
    Phys. Rev. Lett., 81, 148, (1998) [PDF, 222 kB]
  • M. Fischer, P.H.M. van Loosdrecht, G. Güntherodt, B. Büchner, T. Lorenz, M. Breuer, J. Zeman, G. Martinez, G. Dhalenne and A. Revcolevschi
    Revival of the spin--Peierls transition in Cu1-xZnxGeO3 under pressure
    Phys. Rev. B, 57, 7749, (1998) [PDF, 128 kB]
  • K. Fabricius, A. Klümper, U. Löw, B. Büchner, T. Lorenz, G. Dhalenne and A. Revcolevschi
    Reexamination of the microscopic couplings of the quasi-one-dimensional antiferromagnet CuGeO3
    Phys. Rev. B, 57, 1102, (1998) [PDF, 125 kB]
  • T. Lorenz
    Thermodynamische Eigenschaften des Spin-Peierls-Systems CuGeO3
    PhD thesis, Universität zu Köln, (1998) [PDF, 2232 kB]

1997

  • U. Köbler, J. Schweizer, P. Chieux, T. Lorenz, B. Büchner, W. Schnelle, F. Deloie and W. Zinn
    Evidence for biquadratic exchange interactions in GdAg1-xZnx
    J. Magn. Magn. Mater., 170, 110, (1997) [PDF, 11451 kB]
  • T. Lorenz, H. Kierspel, S. Kleefisch, B. Büchner, E. Gamper, A. Revcolevschi and G. Dhalenne
    Specific heat, thermal expansion, and pressure dependencies of the transition temperatures of doped CuGe03
    Phys. Rev. B, 56, R501, (1997) [PDF, 114 kB]
  • T. Lorenz, U. Ammerahl, T. Auweiler, B. Büchner, A. Revcolevschi and G. Dhalenne
    Temperature and magnetic-field dependence of the lattice constant in the spin-Peierls cuprate CuGe03 studied by capacitance dilatometry in fields up to 16 T
    Phys. Rev. B, 55, 5914, (1997) [PDF, 315 kB]
  • U. Ammerahl, T. Lorenz, B. Büchner, A. Revcolevschi and G. Dhalenne
    Magnetostriction of the spin-Peierls cuprate CuGe03
    Z. Phys. B, 102, 71, (1997)
  • U. Ammerahl, T. Lorenz, B. Büchner, A. Revcolevschi and G. Dhalenne
    Magnetostriction of the spin-Peierls cuprate CuGe03
    Z. Phys. B, 102, 71, (1997) [PDF, 574 kB]

1996

  • T. Lorenz, U. Ammerahl, R. Ziemes, B. Büchner, A. Revcolevschi and G. Dhalenne
    Thermodynamic properties of the incommensurate phase of CuGe03
    Phys. Rev. B, 54, R15610, (1996) [PDF, 96 kB]
  • B. Büchner, U. Ammerahl, T. Lorenz, W. Brenig, G. Dhalenne and and A. Revcolevschi
    Magnetic Frustration Induced Formation of the Spin-Peierls Phase in CuGe03: Experimental Evidence
    Phys. Rev. Lett., 77, 1624, (1996) [PDF, 144 kB]

1994

  • Th. Auweiler, T. Lorenz, W. Schlabitz, H. Kierspel, B. Büchner, A. Freimuth, H. Micklitz, I. Tanaka and H. Kojima
    Thermal Expansion of a La1.87Sr0.13CuO4 Single Crystal at Tc in High Magnetic Fields
    Physica C, 235, 1931, (1994) [PDF, 248 kB]
  • T. Lorenz
    Aufbau eines Magnetkryostaten und Messungen der thermischen Ausdehnung von La1.87Sr0.13CuO4 im transversalen Magnetfeld
    Diploma thesis, Universität zu Köln, (1994)