Impact of strong disorder on the static magnetic properties of the spin-chain compound BaCu2SiGeO7

Abstract

The disordered quasi-1D magnet BaCu2SiGeO7 is considered as one of the best physical realizations of the random Heisenberg chain model, which features an irregular distribution of the exchange parameters and whose ground state is predicted to be the scarcely investigated random-singlet state (RSS). Based on extensive 29Si NMR and magnetization studies of BaCu2SiGeO7, combined with numerical Quantum Monte Carlo simulations, we obtain remarkable quantitative agreement with theoretical predictions of the random Heisenberg chain model and strong indications for the formation of a random-singlet state at low temperatures in this compound. As a local probe, NMR is a well-adapted technique for studying the magnetism of disordered systems. In this case it also reveals an additional local transverse staggered field (LTSF), which affects the low-temperature properties of the RSS. The proposed model Hamiltonian satisfactorily accounts for the temperature dependence of the NMR line shapes.

10 pages, 7 figures

References in corpus (6)

• Generalized Directed Loop Method for Quantum Monte Carlo Simulations
• Uniform and staggered magnetizations induced by Dzyaloshinskii-Moriya interactions in isolated and coupled spin 1/2 dimers in a magnetic field
• Spin pseudogap in Ni-doped SrCuO2
• Spin ladders and quantum simulators for Luttinger liquids
• Ordering in weakly coupled random singlet spin chains
• Exchange integrals and magnetization distribution in BaCu2X2O7 (X=Ge,Si)

Cited by in corpus (10)

• Quantum spin chains with frustration due to Dzyaloshinskii-Moriya interactions
• Dynamical properties of the $S=\frac{1}{2}$ random Heisenberg chain
• Signature of a randomness-driven spin-liquid state in a frustrated magnet
• Griffiths Singularities in the Random Quantum Ising Antiferromagnet: A Tree Tensor Network Renormalization Group Study
• Fractional and composite excitations of antiferromagnetic quantum spin trimer chains
• The correlation functions of certain random antiferromagnetic spin-1/2 critical chains
• From order to randomness: Onset and evolution of the random-singlet state in bond-disordered BaCu${}_2$(Si${}_{1-x}$Ge${}_x$)${}_2$O${}_7$ spin-chain compounds
• Effects of quantum impurity spins on the magnetic properties of zigzag and linear spin chains
• Antiferromagnetic order in weakly coupled random spin chains
• Possible realization of a randomness-driven quantum disordered state in an S = 1/2 antiferromagnet Sr3CuTa2O9