Low dimensionality enhances quantum fluctuations, triggering novel states of quantum matter to emerge. In real materials, low dimensionality usually arises from spatially strongly anisotropic couplings. Here, we demonstrate a different mechanism: in two-dimensional systems with coupled alternating ferromagnetic (FM) and antiferromagnetic (AFM) spin- $1/2$ chains, an applied magnetic field may drive a dimensional reduction. Under magnetic field, the FM chains polarize and stiffen, suppressing the propagation of transverse AFM fluctuations from one chain to another, and effectively induce one-dimensional behavior at low energies. For a model describing botallackite, Cu $_2$ (OH) $_3$ Br, quantum Monte Carlo dynamics show that beyond a critical magnetic field, the low-energy spectrum reduces to that of a one-dimensional AFM Heisenberg spin- $1/2$ chain with field-dependent incommensurate two-spinon fluctuations, providing clear signatures for inelastic neutron scattering.Low dimensionality enhances quantum fluctuations, triggering novel states of quantum matter to emerge. In real materials, low dimensionality usually arises from spatially strongly anisotropic couplings. Here, we demonstrate a different mechanism: in two-dimensional systems with coupled alternating ferromagnetic (FM) and antiferromagnetic (AFM) spin-$1/2$ chains, an applied magnetic field may drive a dimensional reduction. Under magnetic field, the FM chains polarize and stiffen, suppressing the propagation of transverse AFM fluctuations from one chain to another, and effectively induce one-dimensional behavior at low energies. For a model describing botallackite, Cu$_2$(OH)$_3$Br, quantum Monte Carlo dynamics show that beyond a critical magnetic field, the low-energy spectrum reduces to that of a one-dimensional AFM Heisenberg spin-$1/2$ chain with field-dependent incommensurate two-spinon fluctuations, providing clear signatures for inelastic neutron scattering.

arXiv:2608.04096Aug 4, 20260 citations

Characterizing ground states of low-dimensional quantum magnets

Hyejin Ju

Jan 1, 20130 citations

2012 CORRELATED ELECTRON SYSTEMS GRC AND GRS, JUNE 23-29, 2012

Steven Allan Kivelson

The 2012 Gordon Conference on Correlated Electron Systems will present cutting-edge research on emergent properties arising from strong electronic correlations. While we expect the discussion at the meeting to be wide-ranging, given the breadth of the title subject matter, we have chosen several topics to be the particular focus of the talks. These are New Developments in Single and Bilayer Graphene, Topological States of Matter, including Topological Insulators and Spin Liquids, the Interplay Between Magnetism and Unconventional Superconductivity, and Quantum Critical Phenomena in Metallic Systems. We also plan to have shorter sessions on Systems Far From Equilibrium, Low Dimensional Electron Fluids, and New Directions (which will primarily focus on new experimental methodologies and their interpretation).The 2012 Gordon Conference on Correlated Electron Systems will present cutting-edge research on emergent properties arising from strong electronic correlations. While we expect the discussion at the meeting to be wide-ranging, given the breadth of the title subject matter, we have chosen several topics to be the particular focus of the talks. These are New Developments in Single and Bilayer Graphene, Topological States of Matter, including Topological Insulators and Spin Liquids, the Interplay Between Magnetism and Unconventional Superconductivity, and Quantum Critical Phenomena in Metallic Systems. We also plan to have shorter sessions on Systems Far From Equilibrium, Low Dimensional Electron Fluids, and New Directions (which will primarily focus on new experimental methodologies and their interpretation).

Jun 29, 20120 citations

Novel quantum magnetic states in low dimensions

Peng Li

Jan 1, 20060 citations

Magnetic Field Effects in Low-Dimensional Quantum Magnets

Adam Iaizzi

Springer thesesJan 1, 20186 citations

Metamagnetic Transition in Low-Dimensional Site-Decorated Quantum Heisenberg Ferrimagnets

Weiguo Yin, A. M. Tsvelik

The prohibition of finite-temperature phase transition in one-dimensional (1D) Ising models and 1D/2D quantum Heisenberg models with short-range interactions fundamentally constrains the application potentials of low-dimensional magnetic materials. Recently, ultranarrow phase crossover (UNPC), which can approach a transition at a desirable finite temperature $T_0$ arbitrarily closely, was discovered in 1D decorated Ising chains and ladders. Here we present a theoretical study of similarly decorated, yet much more challenging, quantum Heisenberg ferrimagnets in a magnetic field, which features ferromagnetic backbone exchange $J$ , antiferromagnetic site-decoration coupling $J_{AF}$ , and different magnetic moments for the backbone and decorating spins $μ_aS_a<μ_bS_b$ . We exactly solved the model in the large $J$ limit -- as a central-macrospin model -- and found two finite-temperature second-order transitions; just above $T_{c2}$ a ``half-ice, half-fire'' regime appears. Finite- $J$ weak-field results follow from an effective-field mapping, suggesting the emergence of UNPC at finite $T_0$ in 2D square lattices thanks to its exponentially strong initial magnetic susceptibility $χ_0\propto e^{4πS_a^2 J/T_0}$ , though less likely in 1D chains where $χ_0\propto J/T_0$ . These results may shed light on new technological applications of low-dimensional quantum spin systems and attract experimental and computational tests.The prohibition of finite-temperature phase transition in one-dimensional (1D) Ising models and 1D/2D quantum Heisenberg models with short-range interactions fundamentally constrains the application potentials of low-dimensional magnetic materials. Recently, ultranarrow phase crossover (UNPC), which can approach a transition at a desirable finite temperature $T_0$ arbitrarily closely, was discovered in 1D decorated Ising chains and ladders. Here we present a theoretical study of similarly decorated, yet much more challenging, quantum Heisenberg ferrimagnets in a magnetic field, which features ferromagnetic backbone exchange $J$, antiferromagnetic site-decoration coupling $J_{AF}$, and different magnetic moments for the backbone and decorating spins $μ_aS_a<μ_bS_b$. We exactly solved the model in the large $J$ limit -- as a central-macrospin model -- and found two finite-temperature second-order transitions; just above $T_{c2}$ a ``half-ice, half-fire'' regime appears. Finite-$J$ weak-field results follow from an effective-field mapping, suggesting the emergence of UNPC at finite $T_0$ in 2D square lattices thanks to its exponentially strong initial magnetic susceptibility $χ_0\propto e^{4πS_a^2 J/T_0}$, though less likely in 1D chains where $χ_0\propto J/T_0$. These results may shed light on new technological applications of low-dimensional quantum spin systems and attract experimental and computational tests.

cond-mat.str-elCross-listedarXiv:2511.06442Nov 11, 20250 citations

1/2

chains, an applied magnetic field may drive a dimensional reduction. Under magnetic field, the FM chains polarize and stiffen, suppressing the propagation of transverse AFM fluctuations from one chain to another, and effectively induce one-dimensional behavior at low energies. For a model describing botallackite, Cu

_2

(OH)

_3

Br, quantum Monte Carlo dynamics show that beyond a critical magnetic field, the low-energy spectrum reduces to that of a one-dimensional AFM Heisenberg spin-

1/2

chain with field-dependent incommensurate two-spinon fluctuations, providing clear signatures for inelastic neutron scattering.

T_0

arbitrarily closely, was discovered in 1D decorated Ising chains and ladders. Here we present a theoretical study of similarly decorated, yet much more challenging, quantum Heisenberg ferrimagnets in a magnetic field, which features ferromagnetic backbone exchange

J

, antiferromagnetic site-decoration coupling

J_{AF}

, and different magnetic moments for the backbone and decorating spins

μ_aS_a<μ_bS_b

. We exactly solved the model in the large

J

limit -- as a central-macrospin model -- and found two finite-temperature second-order transitions; just above

T_{c2}

a ``half-ice, half-fire'' regime appears. Finite-

J

weak-field results follow from an effective-field mapping, suggesting the emergence of UNPC at finite

T_0

in 2D square lattices thanks to its exponentially strong initial magnetic susceptibility

χ_0\propto e^{4πS_a^2 J/T_0}

, though less likely in 1D chains where

χ_0\propto J/T_0

. These results may shed light on new technological applications of low-dimensional quantum spin systems and attract experimental and computational tests.