Nodal quasiparticle in pseudogapped colossal magnetoresistivemanganites

Journal Article · Thu Jan 17 04:00:00 EST 2008 · Nature

OSTI ID:926585

Mannella, Norman; Yang, Wanli L; Zhou, Xing Jiang; Zheng, Hong; Mitchell, John F; Zaanen, Jan; Devereaux, Thomas P; Nagaosa, Naoto; Hussain, Zahid; Shen, Zhi-Xun

A characteristic feature of the copper oxidehigh-temperaturesuperconductors is the dichotomy between the electronicexcitations along the nodal (diagonal) and antinodal (parallel to the CuO bonds) directions in momentum space, generally assumed to be linked tothe 'd-wave' symmetry of the superconducting state. Angle-resolvedphotoemission measurements in the superconducting state have revealed aquasiparticle spectrum with a d-wave gap structure that exhibits amaximum along the antinodal direction and vanishes along the nodaldirection1. Subsequent measurements have shown that, at low dopinglevels, this gap structure persists even in the high-temperature metallicstate, although the nodal points of the superconducting state spread outin finite 'Fermi arcs'2. This is the so-called pseudogap phase, and ithas been assumed that it is closely linked to the superconducting state,either by assigning it to fluctuating superconductivity3 or by invokingorders which are natural competitors of d-wave superconductors4, 5. Herewe report experimental evidence that a very similar pseudogap state witha nodal-antinodal dichotomous character exists in a system that ismarkedly different from a superconductor: the ferromagnetic metallicgroundstate of the colossal magnetoresistive bilayer manganiteLa1.2Sr1.8Mn2O7. Our findings therefore cast doubt on the assumption thatthe pseudogap state in the copper oxides and the nodal-antinodaldichotomy are hallmarks of the superconductivity state.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US); Advanced Light Source(ALS)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 926585
• Report Number(s): LBNL--61366; BnR: YN0100000
• Journal Information: Nature, Journal Name: Nature Vol. 438
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CMR quasiparticle angle resolved photoelectron spectroscopymanganites