2002/12/31 by H. Nojiri, Hiroyuki Nojiri, Hiroshi Kageyama +4 · 2 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Atomic physics #Bound state #Condensed matter physics #Excitation #Excited state #Ground state #Magnetic and transport properties of perovskites and related materials #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Singlet fission #Singlet state #Spin (aerodynamics) #Spins #Triplet state #cond-mat.str-el
paper · pdf · doi:10.1143/jpsj.72.3243
published as J. Phys. Soc. Jpn. 72 (2003) 3243-3253 · 12 pages, 12 figures, submitted to J. Phys. Soc. Jpn. minor change is made
arxiv created 2003/04/27 · openalex publication_date 2003/12/15 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The excited state energy spectrum of a two-dimensional dimer system SrCu2(BO3)2 has been investigated by high field ESR. Various types of multiple-triplet bound states-excited singlet, triplet and quintet states are identified, besides two non-degenerated one-triplet excitations. Extremely strong intensity is found for these higher order bound states, which is an important consequence of the strong suppression of the one-triplet process due to the orthogonality of dimers. A new bound singlet state is found slightly below the energy gap of the one-triplet state, indicating the proximity to a quantum critical point. A band of two-triplet bound state splits into at least eight sharp and discrete levels, which indicates the contribution of distant neighbor interactions. A bound quintet state is observed, which is the direct evidence of two-triplet object made up of four S=1/2 spins. The energy of the lowest quintet becomes lower than that of the one-triplet excitation before the closing of the lowest spin gap. It indicates that the two-triplet bound state touches to the ground singlet state before the one-triplet state does. The present investigation exhibits an essential role of various multiple-triplet bound states in the magnetic excitation spectrum of SrCu2(BO3)2.