Boston University Libraries OpenBU
    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    •   OpenBU
    • BU Open Access Articles
    • BU Open Access Articles
    • View Item
    •   OpenBU
    • BU Open Access Articles
    • BU Open Access Articles
    • View Item

    Field-driven quantum phase transitions in S=1/2 spin chains

    Thumbnail
    Date Issued
    2017-05-25
    Publisher Version
    10.1103/PhysRevB.95.174436
    Author(s)
    Iaizzi, Adam
    Damle, Kedar
    Sandvik, Anders W.
    Share to FacebookShare to TwitterShare by Email
    Export Citation
    Download to BibTex
    Download to EndNote/RefMan (RIS)
    Metadata
    Show full item record
    Permanent Link
    https://hdl.handle.net/2144/28876
    Citation (published version)
    Iaizzi, A., Damle, K., & Sandvik, A. W. (2017). Field-driven quantum phase transitions in S= 1/2 spin chains. Physical Review B, 95(17), 174436.
    Abstract
    We study the magnetization process of a 1D extended Heisenberg model, the J-Q model, as a function of an external magnetic field. In this model, J represents the traditional antiferromagnetic Heisenberg exchange and Q is the strength of a competing four-spin interaction. Without external field, this system hosts a twofold-degenerate dimerized (valence-bond solid) state above a critical value qc≈0.85 where q≡Q/J. The dimer order is destroyed and replaced by a partially polarized translationally invariant state at a critical field value. We find magnetization jumps (metamagnetism) between the partially polarized and fully polarized state for q>qmin, where we have calculated qmin=2/9 exactly. For q>qmin two magnons (flipped spins on a fully polarized background) attract and form a bound state. Quantum Monte Carlo studies confirm that the bound state corresponds to the first step of an instability leading to a finite magnetization jump for q>qmin. Our results show that neither geometric frustration nor spin-anisotropy are necessary conditions for metamagnetism. Working in the two-magnon subspace, we also find evidence pointing to the existence of metamagnetism in the unfrustrated J1-J2 chain (J1>0, J2<0), but only if J2 is spin-anisotropic. We also investigate quantum-critical scaling near the transition into the fully polarized state for q≤qmin at T>0. While the expected `zero-scale-factor' universality is clearly seen for q=0 and q≪qmin; closer to qmin we find that extremely low temperatures are required to observe the asymptotic behavior, due to the influence of the tricritical point at qmin, which leads to a cross-over at a temperature T∗(q) between logarithmic tricritical scaling and zero-scale-factor universality, with T∗(q)→0 when q→qmin.
    Collections
    • BU Open Access Articles [3664]
    • CAS: Physics: Scholarly Papers [346]


    Boston University
    Contact Us | Send Feedback | Help
     

     

    Browse

    All of OpenBUCommunities & CollectionsIssue DateAuthorsTitlesSubjectsThis CollectionIssue DateAuthorsTitlesSubjects

    Deposit Materials

    LoginNon-BU Registration

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Boston University
    Contact Us | Send Feedback | Help