title: Null orbital frustration at the pseudogap boundary in a layered cuprate superconductor.
abstract: We assess the relative importance of orbital frustration at the pseudogap closing field H(pg). Using interlayer tunneling transport in pulsed magnetic fields nearly up to 60 T, we track the field-temperature (H-T) phase diagram for fields parallel ( parallel ab) and normal ( parallel c) to the layered structure of Bi(2)Sr(2)CaCu(2)O(8+y). In contrast to large orientational anisotropy of the superconducting state related to the orbital motion of Cooper pairs, we find anisotropy of H(pg) temperature independent and small, due solely to the g factor. The obtained Zeeman relation with the pseudogap temperature T small star, filled, g( parallel c)micro(B)H( parallel c)(pg)=g( parallel ab)micro(B)H( parallel ab)(pg) approximately k(B)T small star, filled, is fully consistent with the correlations only in the spin channel.
authors.affiliation: IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
authors.forename: L
authors.initials: L
authors.lastname: Krusin-Elbaum
authors.forename: T
authors.initials: T
authors.lastname: Shibauchi
authors.forename: C H
authors.initials: CH
authors.lastname: Mielke