2011/03/31 by Franziska Hammerath, F. Hammerath, Satoshi Nishimoto +13
Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Heisenberg model #Impurity #Materials science #Nuclear magnetic resonance #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Spin (aerodynamics) #Theoretical and Computational Physics #Thermodynamics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.107.017203
published as Phys. Rev. Lett. 107, 017203 (2011) · 4 pages, 4 figures
arxiv created 2011/06/30 · openalex publication_date 2011/06/30 · arxiv updated 2011/07/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report a comparative study of 63Cu nuclear magnetic resonance spin lattice relaxation rates T1^\ensuremath-1 on undoped SrCuO2 and Ca-doped Sr0.9Ca0.1CuO2 spin chain compounds. A temperature independent T1^\ensuremath-1 is observed for SrCuO2 as expected for an S=1/2 Heisenberg chain. Surprisingly, we observe an exponential decrease of T1^\ensuremath-1 for T<90 K in the Ca-doped sample evidencing the opening of a spin gap. The data analysis within the J1\mathrm\text\ensuremath-J2 Heisenberg model employing density-matrix renormalization group calculations suggests an impurity driven small alternation of the J2-exchange coupling as a possible cause of the spin gap.