Atacamite Cu${}_2$Cl(OH)${}_3$ in High Magnetic Fields: Quantum Criticality and Dimensional Reduction of a Sawtooth-Chain Compound

Abstract

We report an extensive high-field study of atacamite Cu${}_2$Cl(OH)${}_3$, a material realization of quantum sawtooth chains with weak interchain couplings, in continuous and pulsed magnetic fields up to 58 T. In particular, we have mapped the entropy landscape for fields as high as 35 T and have identified a field-induced quantum critical point at 21.9(1) T for $\mathbf{H}\parallel c$ axis. The quantum critical point separates field regions with and without magnetic order, evidenced by our thermodynamic study and ${}^1$H nuclear magnetic resonance spectroscopy, but lies far below full saturation of the magnetization. Corroborated by numerical results using density-matrix renormalization group (DMRG) calculations, we find this behavior associated with a dimensional reduction of the spin system: the sawtooth chain effectively decouples into an antiferromagnetic spin-$1/2$ chain (backbone of the sawtooth chain) in the presence of an exchange field produced by the remaining field-polarized spins.

References in corpus (27)

• Quantum Spin Liquids
• Thermodynamics of Spin S = 1/2 Antiferromagnetic Uniform and Alternating-Exchange Heisenberg Chains
• Universally diverging Grueneisen parameter and the magnetocaloric effect close to quantum critical points
• Macroscopic magnetization jumps due to independent magnons in frustrated quantum spin lattices
• Dimensional reduction at a quantum critical point
• Strongly correlated flat-band systems: The route from Heisenberg spins to Hubbard electrons
• Sign change of the Grueneisen parameter and magnetocaloric effect near quantum critical points
• Exact low-temperature behavior of kagome antiferromagnet at high fields
• Magnetocaloric effect in one-dimensional antiferromagnets
• Exact eigenstates and macroscopic magnetization jumps in strongly frustrated spin lattices
• Frustration and quantum criticality
• Frustrated magnet for adiabatic demagnetization cooling to milli-Kelvin temperatures
• Quantum Topological Excitations: from the Sawtooth Lattice to the Heisenberg Chain
• Magnetocaloric effect in quantum spin-s chains
• Efficient adiabatic demagnetization refrigeration to below 50 mK with UHV compatible Ytterbium diphosphates $A$YbP${}_2$O${}_7$ ($A=$Na, K)
• The magnetic and crystal structure of azurite Cu${}_3$(CO${}_3$)${}_2$(OH)${}_2$ as determined by neutron diffraction
• Magnetization process of atacamite: a case of weakly coupled $S=1/2$ sawtooth chains
• Adiabatic demagnetization refrigeration to mK temperatures with the distorted square lattice magnet NaYbGeO${}_4$
• Quantum phase transitions and dimensional reduction in antiferromagnets with inter-layer frustration
• Enhancement of magnetization plateaus in low dimensional spin systems
• One-dimensionalization by Geometrical Frustration in the Anisotropic Triangular Lattice of the 5d Quantum Antiferromagnet Ca3ReO5Cl2
• Electric field driven flat bands: Enhanced magnetoelectric and electrocaloric effects in frustrated quantum magnets
• Dimensional reduction by pressure in the magnetic framework material CuF${}_2$(D${}_2$O)${}_2$pyz: from spin-wave to spinon excitations
• Magneto- and barocaloric properties of the ferro-antiferromagnetic sawtooth chain
• Noncollinear phase of the antiferromagnetic sawtooth chain
• Nuclear magnetic resonance spectroscopy in pulsed magnetic fields
• Orbital-Induced Crossover of the Fulde-Ferrell-Larkin-Ovchinnikov Phase into Abrikosov-like States

Cited by in corpus (3)

• Magnetosynthesis effect on the structure and ground state of Cu${}^{2+}$-based antiferromagnets
• The Magnetic Ground State of Atacamite Cu${}_2$Cl(OH)${}_3$: The Crucial Role of Frustrated Zigzag Chains Revealed by Inelastic Neutron Scattering
• On flat bands in the $J_1$-$J_2$-$J_3$ XXZ sawtooth chain