Orbitally-selective physics in Ca1.8Sr0.2RuO4

Denys Sutter (UZH)
dsutter@physik.uzh.ch

From the interplay of Hund’s coupling and strong electron correlations in multi-band systems emerge fascinating ground states [1,2]. As an example, very recently, Ca₂RuO₄ has been identified as a unique example of an orbitally differentiated conventional band and Mott insulator [3]. This talk is dedicated to recent angle-resolved photoemission results on Ca_1.8Sr_0.2RuO₄, the critical composition of the metal-insulator transition in the Ca_2-xSr_xRuO₄ series. Incompatible experimental results have led to controversy surrounding its ground state [4,5]. The talk will make a strong effort to present the low-energy band structure and explains its signatures of an orbitally-selective breakdown of the Fermi-liquid concept.

References
[1]    A. Georges et al., Annu. Rev. Condens. Matter Phys. 4, 138 (2013)
[2]    S. Kunkemöller et al., Phys. Rev. Lett. 115, 247201 (2015)
[3]    D. Sutter et al., Nat. Commun. 8, 15176 (2017)
[4]    M. Neupane et al., Phys. Rev. Lett. 103, 097001 (2009)
[5]    A. Shimoyamada et al., Phys. Rev. Lett. 102, 086401 (2009)