Soft phonons and structural phase transitions in La1.875Ba 0.125CuO4

Hiroyuki Kimura, Yukio Noda, Hideto Goka, Masaki Fujita, Kazuyoshi Yamada, Gen Shirane

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Soft phonon behavior associated with a structural phase transition from the low-temperature-orthorhombic (LTO) phase (Bmab symmetry) to the low-temperature-tetragonal (LTT) phase (P42/ncm symmetry) was investigated in La1.875Ba0.125CuO4 using neutron scattering. As temperature decreases, the TO-mode at Z-point softens and approaches to zero energy around Td2 = 62 K, where the LTO-LTT transition occurs. Below Td2, the phonon hardens quite rapidly and its energy almost saturates below 50 K. At Td2, the energy dispersion of the soft phonon along in-plane direction significantly changes while the dispersion along out-of-plane direction is almost temperature independent. Coexistence between the LTO phase and the LTT phase, seen in both the soft phonon spectra and the peak profiles of Bragg reflection, is discussed in context of the order of structural phase transitions.

Original languageEnglish
Pages (from-to)445-449
Number of pages5
Journaljournal of the physical society of japan
Issue number1
Publication statusPublished - 2005 Jan


  • High-T superconductivity
  • Neutron scattering
  • Soft phonon
  • Stripe order
  • Structural phase transition

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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