Spin-orbital entanglement and the breakdown of singlets and triplets in Sr 2RuO 4 revealed by spin- and angle-resolved photoemission spectroscopy

• Verfasst von: Veenstra, C. N. [VerfasserIn]
• Verfasst von: Haverkort, Maurits W. [VerfasserIn]
• Titel: Spin-orbital entanglement and the breakdown of singlets and triplets in Sr 2RuO 4 revealed by spin- and angle-resolved photoemission spectroscopy
• Verf.angabe: C.N. Veenstra, Z.-H. Zhu, M. Raichle, B. M. Ludbrook, A. Nicolaou, B. Slomski, G. Landolt, S. Kittaka, Y. Maeno, J.H. Dil, I.S. Elfimov, M.W. Haverkort, and A. Damascelli
• Fussnoten: Die Ziffern 2 und 4 im Titel sind tiefgestellt ; Gesehen am 27.09.2017
• Titel Quelle: Enthalten in: Physical review letters
• Jahr Quelle: 2014
• Band/Heft Quelle: 112(2014,12) Artikel-Nummer 127002, 5 Seiten
• ISSN Quelle: 1079-7114
• DOI: doi:10.1103/PhysRevLett.112.127002
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1563867346

Abstract

Spin-orbit coupling has been conjectured to play a key role in the low-energy electronic structure of Sr2RuO4. By using circularly polarized light combined with spin- and angle-resolved photoemission spectroscopy, we directly measure the value of the effective spin-orbit coupling to be 130±30 meV. This is even larger than theoretically predicted and comparable to the energy splitting of the dxy and dxz,yz orbitals around the Fermi surface, resulting in a strongly momentum-dependent entanglement of spin and orbital character in the electronic wavefunction. As demonstrated by the spin expectation value ⟨→sk⋅→s−k⟩ calculated for a pair of electrons with zero total momentum, the classification of the Cooper pairs in terms of pure singlets or triplets fundamentally breaks down, necessitating a description of the unconventional superconducting state of Sr2RuO4 in terms of these newly found spin-orbital entangled eigenstates.