Publications by Kazimierz Conder

A quantum magnetic analogue to the critical point of water

Mohamed Zayed, Ludger Weber, Frédéric Mila, Bruce Normand, Henrik Moodysson Rønnow, Julio Antonio Larrea Jiménez, Kazimierz Conder, Ellen Fogh, Christian Rüegg

At the liquid-gas phase transition in water, the density has a discontinuity at atmospheric pressure; however, the line of these first-order transitions defined by increasing the applied pressure terminates at the critical point(1), a concept ubiquitous in ...

2021

Evidence of a Coulomb-Interaction-Induced Lifshitz Transition and Robust Hybrid Weyl Semimetal in Td−MoTe2

Helmuth Berger, Philippe Bugnon, Arnaud Magrez, Joël Mesot, Kazimierz Conder, Jan Hugo Dil

2018

Observation of Weyl nodes and Fermi arcs in tantalum phosphide

Oleg Yazyev, Joël Mesot, Kazimierz Conder, Gabriel Albert Autes

A Weyl semimetal possesses spin-polarized band-crossings, called Weyl nodes, connected by topological surface arcs. The low-energy excitations near the crossing points behave the same as massless Weyl fermions, leading to exotic properties like chiral anom ...

Nature Publishing Group2016

Spiral magnetic phase in Li-doped Na2IrO3

Kazimierz Conder, Sándor Tóth

The doping of the honeycomb lattice compound Na2IrO3 with cations having smaller ionic radius such as lithium was supposed to drive the system into a Kitaev spin liquid phase. Even at the smallest doping level the long range magnetic order, present in the ...

American Physical Society2015

Probing the electron-phonon interaction in correlated systems with coherent lattice fluctuation spectroscopy

Frank van Mourik, Christopher Alexander Arrell, Fabrizio Carbone, Kazimierz Conder, Andreas Helmut Christian Mann, Edoardo Baldini

Tailoring the properties of correlated oxides is accomplished by chemical doping, pressure, temperature, or magnetic field. Photoexcitation is a valid alternative to reach out-of-equilibrium states otherwise inaccessible. Here, we quantitatively estimate t ...

Amer Physical Soc2015

Direct observation of the spin texture in SmB6 as evidence of the topological Kondo insulator

Joël Mesot, Kazimierz Conder, Stefan Peter Muff, Jan Hugo Dil

Topological Kondo insulators have been proposed as a new class of topological insulators in which non-trivial surface states reside in the bulk Kondo band gap at low temperature due to strong spin-orbit coupling. In contrast to other three-dimensional topo ...

Nature Publishing Group2014

Exotic Kondo crossover in a wide temperature region in the topological Kondo insulator SmB6 revealed by high-resolution ARPES

Joël Mesot, Kazimierz Conder, Jan Hugo Dil

Temperature dependence of the electronic structure of SmB6 is studied by high-resolution angle-resolved photoemission spectroscopy (ARPES) down to 1 K. We demonstrate that there is no essential difference for the dispersions of the surface states below and ...

Amer Physical Soc2014

Quantum and thermal ionic motion, oxygen isotope effect, and superexchange distribution in La2CuO4

Sandrine Gerber, Bastien Dalla Piazza, Bruce Normand, Henrik Moodysson Rønnow, Kazimierz Conder, Vera Irina Schnells

We study the zero-point and thermal ionic motion in La2CuO4 by means of high-resolution neutron-diffraction experiments. Our results demonstrate anisotropic motion of O and, to a lesser extent, Cu ions, both consistent with the structure of coupled CuO6 oc ...

2014

Correlated Decay of Triplet Excitations in the Shastry-Sutherland Compound SrCu2(BO3)(2)

Mohamed Zayed, Henrik Moodysson Rønnow, Joël Mesot, Kazimierz Conder

The temperature dependence of the gapped triplet excitations (triplons) in the 2D Shastry-Sutherland quantum magnet SrCu2(BO3)(2) is studied by means of inelastic neutron scattering. The excitation amplitude rapidly decreases as a function of temperature, ...

American Physical Society2014

Temperature dependence of the pressure induced monoclinic distortion in the spin S=1/2 Shastry-Sutherland compound SrCu2(BO3)(2)

Mohamed Zayed, Henrik Moodysson Rønnow, Kazimierz Conder

We investigate the monoclinic distortion that occurs at 4.7 GPa at room temperature in the frustrated Shastry-Sutherland model quantum magnet SrCu2(BO3)(2) as a function of pressure and temperature by means of powder and single crystal angle dispersive syn ...

Elsevier2014

Temperature-dependent electron-phonon coupling in La_{2−x}Sr_{x}CuO_{4} probed by femtosecond x-ray diffraction

Majed Chergui, Paul Beaud, Mathieu Julien Gino Cottet, Krunoslav Prsa, Henrik Moodysson Rønnow, Fabrizio Carbone, Kazimierz Conder, Giulia Fulvia Mancini

The strength of the electron-phonon coupling parameter and its evolution throughout a solid's phase diagram often determines phenomena such as superconductivity, charge- and spin-density waves. Its experimental determination relies on the ability to distin ...

Amer Physical Soc2013

Field-Induced Quantum Soliton Lattice in a Frustrated Two-Leg Spin-1/2 Ladder

Henrik Moodysson Rønnow, Joël Mesot, Shuang Wang, Kazimierz Conder, Siyuan Wang, Christian Rüegg

Based on high-field 31P nuclear magnetic resonance experiments and accompanying numerical calculations, it is argued that in the frustrated S=1/2 ladder compound BiCu2PO6 a field-induced soliton lattice develops above a critical field of μ0Hc1=20.96(7) T. ...

American Physical Society2013

Surface and bulk electronic structure of the strongly correlated system SmB6 and implications for a topological Kondo insulator

Joël Mesot, Kazimierz Conder, Jan Hugo Dil

Recent theoretical calculations and experimental results suggest that the strongly correlated material SmB6 may be a realization of a topological Kondo insulator. We have performed an angle-resolved photoemission spectroscopy study on SmB6 in order to eluc ...

Amer Physical Soc2013

Spin-gap evolution upon Ca doping in the spin-ladder series Sr(14−x)CaxCu24O41 studied by inelastic neutron scattering

Henrik Moodysson Rønnow, Kazimierz Conder, Nikolay Tsyrulin

The spin-gap evolution upon Ca doping in Sr14-xCaxCu24O41 was systematically investigated using inelastic neutron scattering. We discover that the singlet-triplet spin-gap excitation survives in this series with x up to 13, indicating the singlet dimer gro ...

American Physical Society2013

Helical fluctuations in the Raman response of the topological insulator Bi2Se3

Helmuth Berger, Kazimierz Conder

The topological insulator Bi2Se3 shows a Raman-scattering (RS) response related to topologically protected surface states amplified by a resonant interband transition. Most significantly this signal has a characteristic Lorentzian lineshape and spin-helica ...

2011

High oxygen pressure single crystal growth of highly Ca-doped spin ladder compound Sr14-xCaxCu24O41 (x > 12)

Neda Nikseresht Ghanepour, Shuang Wang, Kazimierz Conder

Large size high-quality Ca-doped Sr14-xCaxCu24O41 (x=12.2, 12.6 and 13) spin ladder superconducting single crystals were grown using a modified mirror floating zone furnace with oxygen pressure up to 35 bar. The qualities of the as-grown single crystals we ...

Elsevier2011

Direct Observation of Impurity-Induced Magnetism in a Spin-1/2 Antiferromagnetic Heisenberg Two-Leg Spin Ladder

Joël Mesot, Shuang Wang, Kazimierz Conder, Siyuan Wang

Nuclear magnetic resonance and magnetization measurements were used to probe the magnetic features of single-crystalline Bi(Cu1-xZnx)(2)PO6 with 0 < x < 0.05 at temperatures between 2.6 K and 300 K. The simple line shape of the P-31 NMR signals of the pris ...

American Physical Society2010

Crystal growth and characterization of the dilutable frustrated spin-ladder compound Bi(Cu1-xZnx)(2)PO6

Henrik Moodysson Rønnow, Neda Nikseresht Ghanepour, Shuang Wang, Kazimierz Conder, Siyuan Wang, Christian Rüegg

High quality centimeter size single crystals of Bi(Cu1-xZnx)(2)PO6 (x=0% 1% 5%) have been successfully grown by the Travelling Solvent Floating Zone (TSFZ) technique The crystals were grown with a rate of 1 mm/h in a gas mixture of 20% O-2 in Ar Characteri ...

Elsevier2010

Low-temperature spin-state transition in LaCoO3 investigated using resonant x-ray absorption at the CoK edge

Marco Grioni, Kazimierz Conder

LaCoO3 displays two broad anomalies in the DC magnetic susceptibility chi(DC), occurring, respectively, around 50 K and 500 K. We have investigated the first of them within the 10 K < T < RT temperature range using Co K alpha(1) x-ray absorption spectrosco ...

2006