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Article
Open AccessUnveiling new quantum phases in the Shastry-Sutherland compound SrCu2(BO3)2 up to the saturation magnetic field
Under magnetic fields, quantum magnets often undergo exotic phase transitions with various kinds of order. The discovery of a sequence of fractional magnetization plateaus in the Shastry-Sutherland compound SrCu2
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Article
A quantum magnetic analogue to the critical point of water
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...
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Article
Field-Induced Gap in the Spin-1/2 Heisenberg Chain Compound Cu-Pyrimidine Dinitrate: ESR Studies in Magnetic Fields up to 63 T
Results of electron spin resonance studies of copper pyrimidine dinitrate (Cu-PM, [PM-Cu(NO3)2(H2O)2] n , PM = pyrimidine), a spin-1/2 antiferromagnetic chain material with alter...
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Article
Dynamic spin Jahn-Teller effect in small magnetic clusters
We study the effect of spin-phonon coupling in small magnetic clusters, concentrating on a S=1/2 ring of 4 spins coupled antiferromagnetically. If the phonons are treated as classical variables, there is a cri...
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Article
Strain induced correlation gaps in carbon nanotubes
We calculate the change in the correlation gap of armchair carbon nanotubes with uniaxial elastic strain. We predict that such a stretching will enlarge the correlation gap for all carbon nanotubes by a change...
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Article
Dynamic spin-glass behavior in a disorder-free, two-component model of quantum frustrated magnets
Motivated by the observation of a spin-glass transition in almost disorder-free Kagome antiferromagnets, and by the specific form of the effective low-energy model of the S = 1/2, trimerized Kagome antiferromagne...
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Article
Pseudo-gap and possible Spin-Peierls transition in the vanadium oxide VOSb 2 O 4
We report on the magnetic susceptibility and electron spin resonance measurements on polycrystalline samples of the vanadium oxide VOSb2O4, a quasi-one-dimensional S = 1/2 Heisenberg system. The susceptibility v...
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Article
RVB description of the low-energy singlets of the spin 1/2 kagomé antiferromagnet
Extensive calculations in the short-range RVB (Resonating valence bond) subspace on both the trimerized and the regular (non-trimerized) Heisenberg model on the kagomé lattice show that short-range dimer singlets...
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Article
Plaquette ground state in the two-dimensional SU(4) spin-orbital model
In order to understand the properties of Mott insulators with strong ground state orbital fluctuations, we study the zero temperature properties of the SU(4) spin-orbital model on a square lattice. Exact diagona...
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Article
On the origin of biquadratic exchange in spin 1 chains
One-dimensional spin 1 systems may have a rich phase diagram including Haldane gap and dimerized phases if the usually very small biquadratic exchange becomes significant. We show that this unlikely condition ...
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Article
Magnetization plateaux and jumps in a class of frustrated ladders: A simple route to a complex behaviour
We study the occurrence of plateaux and jumps in the magnetization curves of a class of frustrated ladders for which the Hamiltonian can be written in terms of the total spin of a rung. We argue on the basis o...
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Article
Magnetic properties of the S = 1/2 one-dimensional antiferromagnet MgVO
The magnetic susceptibility and the electron spin resonance in the X-band of the transition metal oxide compound MgVO3 are reported. We show that this compound, made of weakly coupled infinite chains of VO5 pyram...
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Article
Ladders in a magnetic field: a strong coupling approach
We show that non-frustrated and frustrated ladders in a magnetic field can be systematically mapped onto an XXZ Heisenberg model in a longitudinal magnetic field in the limit where the rung coupling is the domina...
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Article
Optical conductivity of the Bechgaard salts: the sum rules revisited
The validity of the optical sum rules has been addressed eversince and was always matter of debate. Particularly controversial is the proof that the partial sum rules can be extended to both optical conductivity ...
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Article
Comparison of tunneling through molecules with Mott-Hubbard and with dimerization gaps
In order to study the tunneling of electrons through an interacting, 1D, dimerized molecule connected to leads, we consider the persistent current in a ring embedding this molecule. We find numerically that, f...
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Chapter and Conference Paper
Calculation of Ni(100) Vibrational Properties Using the Matching Procedure
The matching procedure [1, 2] enables one to calculate the dispersion curves of surface phonon and resonances in a semi-infinite crystal throughout the two-dimensional (2D) Brillouin zone (BZ). Unlike Green’s ...
