Gapless zigzag chain of impurity-substituted YBa2Cu4O8

✍ Scribed by Y. Itoh; N. Watanabe; S. Adachi; T. Machi

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 184 KB
• Volume: 468
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2008.05.040

✦ Synopsis

We report zero field chain-site 63 Cu NQR studies of the low-lying magnetic excitations of CuO zigzag double chains in low-T c and non-superconducting YBa 2 (Cu 1Àx Zn x ) 4 O 8 , YBa 2 (Cu 1Àx Ni x ) 4 O 8 and Y 1Àx Pr x Ba 2 Cu 4 O 8 . For the non-superconducting YBa 2 (Cu 1Àx Zn x ) 4 O 8 with x = 0.03, we observed a non-vanishing behavior of a 63 Cu nuclear spin-lattice relaxation rate divided by temperature 1/T 1 T at low temperatures, that is, the absence of an energy gap in a magnetic excitation spectrum. The gapless magnetic excitation spectrum of the zigzag chains is characteristic of a quasi-one-dimensional Tomonaga-Luttinger liquid. The Zn-, Ni-and Pr-induced stretched exponential 63 Cu nuclear spin-lattice relaxation times suggest that the Zn-induced edge state has different magnetic correlation from Ni and Pr impurities.