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Frédéric Mila

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Publications associées (204)

Supersolid phase induced by correlated hopping in spin-1/2 frustrated quantum magnets

Frédéric Mila, Julien Dorier

We show that correlated hopping of triplets, which is often the dominant source of kinetic energy in dimer-based frustrated quantum magnets, produces a remarkably strong tendency to form supersolid phases in a magnetic field. These phases are characterized ...

2008

First-principles investigation of symmetric and antisymmetric exchange interactions of SrCu2(BO3)(2)

Frédéric Mila

We report on a first-principles investigation of the electronic structure and of the magnetic properties of the quasi-two-dimensional Mott insulator SrCu2(BO3)(2). Based on the hopping integrals and Coulomb interactions calculated with local-density approx ...

2008

Mechanisms for spin supersolidity in S=1/2 spin-dimer antiferromagnets

Jean-David Picon, Frédéric Mila, Nicolas Laflorencie

Using perturbative expansions and the contractor renormalization (CORE) algorithm, we obtain effective hard-core bosonic Hamiltonians describing the low-energy physics of S=1/2 spin-dimer antiferromagnets known to display supersolid phases under an applied ...

2008

Crystallization of the resonating valence bond liquid as vortex condensation

Frédéric Mila, Dmitri Ivanov

We show that the liquid-to-crystal quantum phase transition in the Rokhsar-Kivelson dimer model on the two-dimensional triangular lattice occurs as a condensation of vortexlike excitations called "visons." This conclusion is drawn from numerical studies of ...

2007

Uniform and staggered magnetizations induced by Dzyaloshinskii-Moriya interactions in isolated and coupled spin-1∕2dimers in a magnetic field

Frédéric Mila, Salvatore Manmana

We investigate the interplay of Dzyaloshinskii-Moriya interactions and an external field in spin-1∕2 dimers. For isolated dimers and at low field, we derive simple expressions for the staggered and uniform magnetizations which show that the orientation of ...

2007

Static impurities in the S=3/2 kagome lattice: Exact diagonalization calculations on small clusters

Frédéric Mila, Bruce Normand

We consider the effects of doping the S=3/2 kagome lattice with static, nonmagnetic impurities. By exact-diagonalization calculations on small clusters, we deduce the local spin correlations and magnetization distribution around a vacancy. As in the S=1/2 ...

2007

Phase Separation and Flux Quantization in the Doped Quantum Dimer Model on Square and Triangular Lattices

Frédéric Mila

The doped two-dimensional quantum dimer model is investigated by numerical techniques on the square and triangular lattices, with significantly different results. On the square lattice, at small enough doping, there is always a phase separation between an ...

2007

Wannier functions and exchange integrals: The example ofLiCu2O2

Frédéric Mila

Starting from a single band Hubbard model in the Wannier function basis, we revisit the problem of the ligand contribution to exchange and derive explicit formulas for the exchange integrals in metal oxide compounds in terms of atomic parameters that can b ...

2007

Exotic phenomena in doped quantum magnets

Frédéric Mila

We investigate the properties of a two-dimensional frustrated quantum antiferromagnet on a square lattice, especially at infinitesimal doping. We find that next nearest neighbour (NN) J2 and next–next NN J3 interactions together destroy the antiferromagnet ...

2007

Checkerboard order in the – model on the square lattice

Cédric Weber, Michael Sigrist, Frédéric Mila

We propose that the inhomogeneous patterns seen by STM in some underdoped superconducting cuprates could be related to a bond-order-wave instability of the staggered flux state, one of the most studied “normal” state proposed to compete with the d-wave RVB ...

2007

Ising Phases of Heisenberg Ladders in a Magnetic Field

Frédéric Mila, Karlo Penc

We show that Dzyaloshinskii-Moriya (DM) interactions can substantially modify the phase diagram of spin-1/2 Heisenberg ladders in a magnetic field provided they compete with exchange. For nonfrustrated ladders, they induce a local magnetization along the D ...

2007

Quantum and Thermal Transitions Out of the Supersolid Phase of a 2D Quantum Antiferromagnet

Frédéric Mila, Nicolas Laflorencie

We investigate the thermodynamic properties of a field-induced supersolid phase in a 2D quantum antiferromagnet model. Using quantum Monte Carlo simulations, a very rich phase diagram is mapped out in the temperature—magnetic-field plane, with an extended ...

2007

Identification of an RVB liquid phase in a quantum dimer model with competing kinetic terms

Frédéric Mila, François Vernay

Starting from the mean-field solution of a spin-orbital model of LiNiO2, we derive an effective quantum dimer model (QDM) that lives on the triangular lattice and contains kinetic terms acting on four-site plaquettes and six-site loops. Using exact diagona ...

2006

Magnetism and superconductivity of strongly correlated electrons on the triangular lattice

Cédric Weber, Frédéric Mila, Thierry Giamarchi

We investigate the phase diagram of the t−J model on a triangular lattice using a variational Monte Carlo approach. We use an extended set of Gutzwiller projected fermionic trial wave functions allowing for simultaneous magnetic and superconducting order p ...

2006

Single-particle versus pair condensation of hard-core bosons with correlated hopping

Frédéric Mila, Julien Dorier

We investigate the consequences of correlated hopping on the ground state properties of hard-core bosons on a square lattice as revealed by extensive exact diagonalizations and quantum Monte Carlo simulations. While for noninteracting hard-core bosons the ...

2006

Electronic structure and exchange interactions of Na2V3O7

Frédéric Mila

We have performed first-principle calculations of the electronic structure and exchange couplings for the nanotube compound Na2V3O7 using the local-density approximation Hubbard parameter U approach. Our results show that while the intraring exchange inter ...

2006

Doping quantum dimer models on the square lattice

Frédéric Mila

A family of models is proposed to describe the motion of holes in a fluctuating quantum dimer background on the square lattice. Following Castelnovo et al. [Ann. Phys. (N.Y.) 318, 316 (2005)], a generalized Rokhsar-Kivelson Hamiltonian at finite doping whi ...

2006

Frustrated three-leg spin tubes: From spin1∕2with chirality to spin3∕2

Frédéric Mila

Motivated by the recent discovery of the spin tube [(CuCl2tachH)3Cl]Cl2, we investigate the properties of a frustrated three-leg spin tube with antiferromagnetic intra- and inter-ring couplings. We pay special attention to the evolution of the properties f ...

2006

Field-Induced Staggered Magnetization and Magnetic Ordering inCu2(C5H12N2)2Cl4

Frédéric Mila

We present a 2D NMR investigation of the gapped spin-1/2 compound Cu2(C5H10N2D2)2Cl4. Our measurements reveal the presence of a magnetic field-induced transverse staggered magnetization (TSM) which persists well below and above the field-induced 3D long-ra ...

2006

Orbital selective overlayer-substrate hybridization in a Pb monolayer on Ag(111)

Thomas Gloor, Harald Brune, Klaus Kern, Marco Grioni, Stephan Fedrigo, Frédéric Mila, Daniela Pacilè

The electronic structure of a Pb overlayer on Ag(111) has been studied by angle-resolved photoemission spectroscopy. We identify three p bands. While the p(xy) bands are sharp and closely resemble the corresponding bands of a free-standing Pb layer, the p( ...

2006

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