2013/11/25 by Dirk Wulferding, Angela Möller, Kwang‐Yong Choi +11
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.88.205136
published as Phys. Rev. B 88, 205136 (2013)
openalex publication_date 2013/11/25 · arxiv created 2013/11/26 · arxiv updated 2013/11/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
In the s=1/2 antiferromagnetic spin chain material TiPO4, the formation of a spin gap takes place in a two-step process with two characteristic temperatures, T*=111 K and TSP=74 K. We observe an unusual lattice dynamics over a large temperature regime as well as evidence for an orbital instability preceding the spin-Peierls transition. We relate different intrachain exchange interactions of the high temperature compared to the spin-Peierls phase to a modification of the orbital ordering pattern. In particular, our observation of a high-energy excitation of mixed electronic and lattice origin suggests an exotic dimerization process different from other spin-Peierls materials.