Is the pseudogap in the high T{sub c} cuprates evidence for dynamic van Hove Jahn-Teller effects?
- Northeastern Univ., Boston, MA (United States)
Angle-resolved photoemission has demonstrated that in optimally doped YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}, the van Hove singularity (vHs) is pinned close to the Fermi level. Such a pinning was predicted by the vHs scenario, due to strong electron-phonon coupling. This coupling arises for a novel Jahn-Teller (JT) effect, in which a structural distortion splits the degeneracy of the two vHs`s. In the lanthanum cuprates, there appears to be a sequence of dynamic JT phases, possibly terminating in a low-temperature static JT phase. The highest-temperature JT phase corresponds to the onset of octahedral tilts in the La cuprates (pyramidal tilts in YBCO), can can be identified with the experimentally observed pseudogap phase. Here the author summarizes recent experimental evidence for such a dynamic JT effect in the cuprates.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 207185
- Journal Information:
- Journal of Superconductivity, Vol. 8, Issue 5; Other Information: PBD: Oct 1995
- Country of Publication:
- United States
- Language:
- English
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