2008/10/31 by Gang Chen, Leon Balents, Andreas P. Schnyder · 99 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Excited state #Hamiltonian (control theory) #Magnetic and transport properties of perovskites and related materials #Multiferroics and related materials #Phase (matter) #Phase diagram #Phase transition #Physics #Quantum mechanics #Quantum phase transition #Quantum phases #Singlet state #Spin (aerodynamics) #Thermodynamics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.102.096406
published in Physical Review Letters 102(9), 096406 (American Physical Society) · 4+ pages, 2 figures, minor corrections
arxiv created 2008/11/01 · openalex publication_date 2009/03/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a theory of spin and orbital physics in the A-site spinel compound FeSc2S4, which experimentally exhibits a broad "spin-orbital liquid" regime. A spin-orbital Hamiltonian is derived from a combination of microscopic consideration and symmetry analysis. We demonstrate a keen competition between spin-orbit interactions, which favor formation of a local "spin-orbital singlet," and exchange, which favors magnetic and orbital ordering. Separating the spin-orbital singlet from the ordered state is a quantum critical point. We argue that FeSc2S4 is close to this quantum critical point on the spin-orbital singlet side. The full phase diagram includes a commensurate-incommensurate transition within the ordered phase. A variety of comparisons to and suggestions for experiments are discussed.