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Christian Rüegg

Cette personne a quitté l’EPFL

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Publications associées (24)

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Field-controlled magnetic order in the quantum spin-ladder system (Hpip)2CuBr4

Henrik Moodysson Rønnow, Joël Mesot, Bruce Normand, Christian Rüegg, Pierre Bouillot, Daniel Biner

Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: ...

2009

Ultrafast frustration breaking and magnetophononic driving of singlet excitations in a quantum magnet

Bruce Normand, Nicola Colonna, Christian Rüegg

Ideal magnetic frustration forms the basis for the emergence of exotic quantum spin states that are entirely nonmagnetic. Such singlet spin states are the defining feature of the Shastry-Sutherland model, and of its faithful materials realization in the qu ...

2023

Revealing three-dimensional quantum criticality by Sr substitution in Han purple

Frédéric Mila, Bruce Normand, Gregory Scott Tucker, Christian Rüegg

Classical and quantum phase transitions (QPTs), with their accompanying concepts of criticality and universality, are a cornerstone of statistical thermodynamics. An excellent example of a controlled QPT is the field-induced ordering of a gapped quantum ma ...

2021

Structural and magnetic properties of β-Li2IrO3 after grazing-angle focused ion beam thinning

Christian Rüegg

Manipulating the size and orientation of quantum materials is often used to tune emergent phenomena, but precise control of these parameters is also necessary from an experimental point of view. Various synthesis techniques already exist, such as epitaxial ...

2025

Magnetic order in the quasi-one-dimensional Ising system RbCoCl3

Bruce Normand, Christian Rüegg

In RbCoCl3, the magnetic Co2+ ions form weakly coupled Ising chains arranged on a triangular lattice. We have investigated the structure and magnetism in RbCoCl3 by high-resolution x-ray diffraction and neutron scattering measurements on powder and single- ...

2021

Thermal Control of Spin Excitations in the Coupled Ising-Chain Material RbCoCl3

Bruce Normand, Christian Rüegg

We have used neutron spectroscopy to investigate the spin dynamics of the quantum (S = 1/2) antiferromagnetic Ising chains in RbCoCl3. The structure and magnetic interactions in this material conspire to produce two magnetic phase transitions at low temper ...

2020

Bound States and Field-Polarized Haldane Modes in a Quantum Spin Ladder

Bruce Normand, Christian Rüegg, Pierre Bouillot, Daniel Biner

The challenge of one-dimensional systems is to understand their physics beyond the level of known elementary excitations. By high-resolution neutron spectroscopy in a quantum spin-ladder material, we probe the leading multiparticle excitation by characteri ...

Amer Physical Soc2017

Thermal Evolution of Dirac Magnons in the Honeycomb Ferromagnet CrBr3

Bruce Normand, Christian Rüegg, Andreas Martin Läuchli Herzig

CrBr3 is an excellent realization of the two-dimensional honeycomb ferromagnet, which offers a bosonic equivalent of graphene with Dirac magnons and topological character. We perform inelastic neutron scattering measurements using state-of-the-art instrume ...

2022

CAMEA—A novel multiplexing analyzer for neutron spectroscopy

Henrik Moodysson Rønnow, Christian Rüegg, Felix Groitl

The analyzerdetector system continuous angle multiple energy analysis will be installed on the cold-neutron triple-axis spectrometer RITA-2 at SINQ, PSI. CAMEA is optimized for efficiency in the horizontal scattering plane enabling rapid and detailed mappi ...

American Institute of Physics2016

A quantum magnetic analogue to the critical point of water

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

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

Anisotropic Cascade of Field-Induced Phase Transitions in the Frustrated Spin-Ladder System BiCu_{2}PO_{6}

Henrik Moodysson Rønnow, Christian Rüegg, Krunoslav Prsa, Shuang Wang

BiCu2PO6 is a frustrated two-leg spin-ladder compound with a spin gap that can be closed with a magnetic field of approximately 20 T. This quantum phase transition and its related phase diagram as a function of magnetic field and temperature (H, T) are inv ...

Amer Physical Soc2012

Direct Observation of Magnon Fractionalization in the Quantum Spin Ladder

Henrik Moodysson Rønnow, Joël Mesot, Bruce Normand, Christian Rüegg, Daniel Biner

We measure by inelastic neutron scattering the spin excitation spectra as a function of applied magnetic field in the quantum spin-ladder material (C5H12N)(2)CuBr4. Discrete magnon modes at low fields in the quantum disordered phase and at high fields in t ...

2009

Narrow-band and tunable intense terahertz pulses for mode-selective coherent phonon excitation

Christian Rüegg

We generate frequency-tunable narrow-band intense fields in the terahertz (THz) range by optical rectification of a temporally modulated near-infrared laser pumping a nonlinear organic crystal. Carrier-frequency tunability between 0.5 and 6.5THz is achieve ...

2020

Inelastic x-ray scattering study of superconducting SmFeAsO1-xFy single crystals: Evidence for strong momentum-dependent doping-induced renormalizations of optical phonons

Henrik Moodysson Rønnow, Sergiy Katrych, Christian Rüegg

We report inelastic x-ray scattering experiments on the lattice dynamics in SmFeAsO and superconducting SmFeAsO0.60F0.35 single crystals. Particular attention was paid to the dispersions along the [100] direction of three optical modes close to 23 meV, pol ...

2009

Evidence for spinon localization in the heat transport of the spin-1/2 ladder compound (C5H12N)(2)CuBr4

Henrik Moodysson Rønnow, Christian Rüegg

We present experiments on the magnetic-field-dependent thermal transport in the spin-1/2 ladder system (C5H12N)(2)CuBr4. The thermal conductivity kappa(B) is only weakly affected by the field-induced transitions between the gapless Luttinger-liquid state r ...

2009

Electromagnon dispersion probed by inelastic X-ray scattering in LiCrO2

Henrik Moodysson Rønnow, Christian Rüegg

Inelastic X-ray scattering with meV energy resolution (IXS) is an ideal tool to measure collective excitations in solids and liquids. In non-resonant scattering condition, the cross-section is strongly dominated by lattice vibrations (phonons). However, it ...

Nature Research2016

Tomonaga-Luttinger Liquid Spin Dynamics in the Quasi-One-Dimensional Ising-Like Antiferromagnet BaCo2V2O8

Jonathan White, Martin Mansson, Christian Rüegg, Gregory Scott Tucker

Combining inelastic neutron scattering and numerical simulations, we study the quasi-one-dimensional Ising anisotropic quantum antiferromagnet BaCo2V2O8 in a longitudinal magnetic field. This material shows a quantum phase transition from a Neel ordered ph ...

AMER PHYSICAL SOC2019

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

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

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

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

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

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

Multiple Magnetic Bilayers and Unconventional Criticality without Frustration in BaCuSi2O6

Frédéric Mila, Bruce Normand, Christian Rüegg, Gregory Scott Tucker

The dimerized quantum magnet BaCuSi2O6 was proposed as an example of "dimensional reduction" arising near the magnetic-field-induced quantum critical point (QCP) due to perfect geometrical frustration of its interbilayer interactions. We demonstrate by hig ...

2020