Publications by Karlo Penc | EPFL Graph Search

Time-reversal symmetry breaking Abelian chiral spin liquid in Mott phases of three-component fermions on the triangular lattice

Frédéric Mila, Karlo Penc, Pierre Marcel Nataf, Carolin Boos, Miklos Lajko

We provide numerical evidence in favor of spontaneous chiral symmetry breaking and the concomitant appearance of an Abelian chiral spin liquid for three-component fermions on the triangular lattice described by an SU(3) symmetric Hubbard model with hopping ...

2020

Dimensional crossover in the SU(4) Heisenberg model in the six-dimensional antisymmetric self-conjugate representation revealed by quantum Monte Carlo and linear flavor-wave theory

Frédéric Mila, Karlo Penc, Francisco Hyunkyu Kim

Using linear flavor-wave theory (LFWT) and auxiliary field quantum Monte Carlo (QMC), we investigate the properties of the SU(4) Heisenberg model on the anisotropic square lattice in the fully antisymmetric six-dimensional irreducible representation, a mod ...

2019

Linear flavor-wave theory for fully antisymmetric SU( N ) irreducible representations

Frédéric Mila, Karlo Penc, Pierre Marcel Nataf, Francisco Hyunkyu Kim

The extension of the linear flavor-wave theory to fully antisymmetric irreducible representations (irreps) of SU(N) is presented in order to investigate the color order of SU(N) antiferromagnetic Heisenberg models in several two-dimensional geometries. The ...

2017

Semiclassical theory of the magnetization process of the triangular lattice Heisenberg model

Frédéric Mila, Tommaso Coletta, Karlo Penc, Tamás András Tóth

Motivated by the numerous examples of 1/3 magnetization plateaux in the triangular-lattice Heisenberg antiferromagnet with spins ranging from 1/2 to 5/2, we revisit the semiclassical calculation of the magnetization curve of that model, with the aim of com ...

2016

Plaquette order in the SU(6) Heisenberg model on the honeycomb lattice

Frédéric Mila, Karlo Penc, Pierre Marcel Nataf, Miklos Lajko

We revisit the SU(6) Heisenberg model on the honeycomb lattice, which has been predicted to be a chiral spin liquid by mean-field theory [G. Szirmai et al., Phys. Rev. A 84, 011611(R) (2011)]. Using exact diagonalizations of finite clusters, infinite proje ...

2016

Chiral Spin Liquids in Triangular-LatticeSU(N)Fermionic Mott Insulators with Artificial Gauge Fields

Frédéric Mila, Karlo Penc, Pierre Marcel Nataf, Miklos Lajko

We show that, in the presence of a π/2 artificial gauge field per plaquette, Mott insulating phases of ultracold fermions with SU(N) symmetry and one particle per site generically possess an extended chiral phase with intrinsic topological order characteri ...

2016

Zero-temperature Monte Carlo study of the noncoplanar phase of the classical bilinear-biquadratic Heisenberg model on the triangular lattice

Frédéric Mila, Karlo Penc, Sandro Wenzel

We investigate the ground-state properties of the highly degenerate noncoplanar phase of the classical bilinear-biquadratic Heisenberg model on the triangular lattice with Monte Carlo simulations. For that purpose, we introduce an Ising pseudospin represen ...

2013

Competing states in the SU(3) Heisenberg model on the honeycomb lattice: Plaquette valence-bond crystal versus dimerized color-ordered state

Frédéric Mila, Karlo Penc, Miklos Lajko

Conflicting predictions have been made for the ground state of the SU(3) Heisenberg model on the honeycomb lattice: Tensor network simulations found a plaquette order [Zhao et al., Phys. Rev. B 85, 134416 (2012)], where singlets are formed on hexagons, whi ...

2013

Spin-Orbital Quantum Liquid on the Honeycomb Lattice

Frédéric Mila, Karlo Penc, Miklos Lajko

The main characteristic of Mott insulators, as compared to band insulators, is to host low-energy spin fluctuations. In addition, Mott insulators often possess orbital degrees of freedom when crystal-field levels are partially filled. While in the majority ...

American Physical Society2012

Degeneracy and ordering of the noncoplanar phase of the classical bilinear-biquadratic Heisenberg model on the triangular lattice

Frédéric Mila, Karlo Penc

We investigate the zero-temperature behavior of the classical Heisenberg model on the triangular lattice in which the competition between exchange interactions of different orders favors a relative angle between neighboring spins Phi is an element of (0,2 ...

2012

Three-sublattice order in the SU(3) Heisenberg model on the square and triangular lattice

Frédéric Mila, Karlo Penc

We present a numerical study of the SU(3) Heisenberg model of three-flavor fermions on the triangular and square lattice by means of the density-matrix renormalization group and infinite projected entangled-pair states. For the triangular lattice we confir ...

2012

Simplex solids in SU(N) Heisenberg models on the kagome and checkerboard lattices

Frédéric Mila, Karlo Penc

We present a numerical study of the SU(N) Heisenberg model with the fundamental representation at each site for the kagome lattice (for N = 3) and the checkerboard lattice (for N = 4), which are the line graphs of the honeycomb and square lattices and thus ...

2012

Competition between two- and three-sublattice ordering for S=1 spins on the square lattice

Frédéric Mila, Karlo Penc, Tamás András Tóth

We provide strong evidence that the S = 1 bilinear-biquadratic Heisenberg model with nearest-neighbor interactions on the square lattice possesses an extended three-sublattice phase induced by quantum fluctuations for sufficiently large biquadratic interac ...

2012

Simultaneous Dimerization and SU(4) Symmetry Breaking of 4-Color Fermions on the Square Lattice

Frédéric Mila, Karlo Penc

Using infinite projected entangled-pair states, exact diagonalization, and flavor-wave theory, we show that the SU(4) Heisenberg model undergoes a spontaneous dimerization on the square lattice, in contrast with its SU(2) and SU(3) counterparts, which deve ...

2011

Three-Sublattice Ordering of the SU(3) Heisenberg Model of Three-Flavor Fermions on the Square and Cubic Lattices

Frédéric Mila, Karlo Penc, Tamás András Tóth

Combining a semiclassical analysis with exact diagonalizations, we show that the ground state of the SU(3) Heisenberg model on the square lattice develops three-sublattice long-range order. This surprising pattern for a bipartite lattice with only nearest- ...

2010

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

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

Quadrupolar Phases of theS=1Bilinear-Biquadratic Heisenberg Model on the Triangular Lattice

Frédéric Mila, Karlo Penc

Using mean-field theory, exact diagonalizations, and SU(3) flavor theory, we have precisely mapped out the phase diagram of the S=1 bilinear-biquadratic Heisenberg model on the triangular lattice in a magnetic field, with emphasis on the quadrupolar phases ...

2006

Orbital degeneracy as a source of frustration inLiNiO2

Frédéric Mila, François Vernay, Karlo Penc

2005