Publications de Ioannis Rousochatzakis

Microscopic theory of the nearest-neighbor valence bond sector of the spin-1/2 kagome antiferromagnet

2018

Quantum dimer model for the spin-1/2 kagome Z(2) spin liquid

We revisit the description of the low-energy singlet sector of the spin-1/2 Heisenberg antiferromagnet on kagome in terms of an effective quantum dimer model. With the help of exact diagonalizations of appropriate finite-size clusters, we show that the emb ...

2014

Destruction of valence-bond order in a S=1/2 sawtooth chain with a Dzyaloshinskii-Moriya term

Frédéric Mila, Ioannis Rousochatzakis

A small value of the spin gap in quantum antiferromagnets with strong frustration makes them susceptible to nominally small deviations from the ideal Heisenberg model. One such perturbation, the anisotropic Dzyaloshinskii-Moriya (DM) interaction, is an imp ...

2011

Spin-Peierls instabilities of antiferromagnetic rings in a magnetic field

Frédéric Mila, Karlo Penc, Ioannis Rousochatzakis

Motivated by the intriguing properties of magnetic molecular wheels at field-induced level crossings, we investigate the spin-Peierls instability of antiferromagnetic rings in a field by exact diagonalizations of a microscopic spin model coupled to the lat ...

2009

Dzyaloshinskii-Moriya anisotropy and nonmagnetic impurities in the s=1/2 kagome system ZnCu3(OH)(6)Cl-2

Frédéric Mila, Bruce Normand, Salvatore Manmana, Ioannis Rousochatzakis

Motivated by recent nuclear magnetic resonance experiments on ZnCu3(OH)(6)Cl-2, we present an exact-diagonalization study of the combined effects of nonmagnetic impurities and Dzyaloshinskii-Moriya (DM) interactions in the s = 1/2 kagome antiferromagnet. T ...

2009

Theory of severe slowdown in the relaxation of rings and clusters with antiferromagnetic interactions

Ioannis Rousochatzakis

We show that in the severe slowing-down temperature regime the relaxation of antiferromagnetic rings and similar magnetic nanoclusters is governed by the quasicontinuum portion of their quadrupolar fluctuation spectrum and not by the lowest excitation line ...

2009

Highly frustrated magnetic clusters: The kagome on a sphere

Frédéric Mila, Ioannis Rousochatzakis

We present a detailed study of the low-energy excitations of two existing finite-size realizations of the planar kagome Heisenberg antiferromagnet on the sphere: the cuboctahedron and the icosidodecahedron. After highlighting a number of special spectral f ...

2008

Microscopic theory for the Markovian decay of magnetization fluctuations in nanomagnets

Ioannis Rousochatzakis

We present a microscopic theory for the phonon-driven decay of the magnetization fluctuations in a wide class of nanomagnets where the dominant energy is set by isotropic exchange and/or uniaxial anisotropy. Based on the Zwanzig-Mori projection formalism, ...

2007