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Orbitally-selective physics in Ca_2RuO_4 and Ca_1.8Sr_0.2RuO_4

6 Febbraio 2018 10:00 - 11:00
14 - 15 IV piano St. 9
Physik-Institut, Universit?t Z?rich, Laboratory for Quantum Matter Research 8001 Z?rich, Switzerland
Area di Ricerca
Superconduttivita', Sistemi fortemente correlati, Eterostrutture e loro applicazioni

Ca2RuO4 is an archetypal example for multi-band Mott physics including spin-orbit and Hund`s coupling [1,2]. For decades, the mechanism underlying its Mott insulating state has remained elusive [3-5]. The first half of this talk will present the complete low-energy ruthenium band structure as observed by ARPES in the paramagnetic insulating state of Ca2RuO4. These results suggest that Ca2RuO4 is a unique example of an orbital differentiated conventional band and Mott insulator [6]. The talk will make a strong effort to explain how this conclusion is reached independently from both DMFT calculations and a purely phenomenological DFT model. The second half of the talk is dedicated to recent ARPES results on Ca1.8Sr0.2RuO4, the critical composition of the metal-insulator transition. Incompatible experimental results have led to controversy surrounding its ground state [7,8]. Here I will present the low-energy band structure and demonstrate 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. Kunkem?ller et al., Phys. Rev. Lett. 115, 247201 (2015) [3] V. Anisimov et al., Eur. Phys. J. B 25, 191 (2002) [4] A. Liebsch & H. Ishida, Phys. Rev. Lett. 98, 216304 (2007) [5] E. Gorelov et al., Phys. Rev. Lett. 104, 226401 (2010) [6] D. Sutter et al., Nat. Commun. 8, 15176 (2017) [7] M. Neupane et al., Phys. Rev. Lett. 103, 097001 (2009) [8] A. Shimoyamada et al., Phys. Rev. Lett. 102, 086401 (2009)


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