Origin of the exciton mass in the frustrated Mott insulator Na2IrO3 Journal Article

Author(s): Alpichshev, Zhanybek; Sie, Edbert J; Mahmood, Fahad; Cao, Gang; Gedik, Nuh
Article Title: Origin of the exciton mass in the frustrated Mott insulator Na2IrO3
Abstract: We use a three-pulse ultrafast optical spectroscopy to study the relaxation processes in a frustrated Mott insulator Na2IrO3. By being able to independently produce the out-of-equilibrium bound states (excitons) of doublons and holons with the first pulse and suppress the underlying antiferromagnetic order with the second one, we were able to elucidate the relaxation mechanism of quasiparticles in this system. By observing the difference in the exciton dynamics in the magnetically ordered and disordered phases we found that the mass of this quasiparticle is mostly determined by its interaction with the surrounding spins.
Journal Title: Physical Review B
Volume: 96
Issue 23
ISSN: 24699950
Publisher: American Physical Society  
Date Published: 2017-12-26
Start Page: Article number: 235141
DOI: 10.1103/PhysRevB.96.235141
Notes: Z.A. gratefully acknowledges discussions with P. A. Lee and A. Kemper. A conversation with J. Zaanen was instrumental in clarifying the physical picture described in this paper. We would also like to thank A. Kogar for thoroughly reading the manuscript and making valuable comments. This work was supported by Army Research Office Grant No. W911NF-15-1-0128 and Gordon and Betty Moore Foundation EPiQS Initiative through Grant No. GBMF4540 (time resolved optical spectroscopy), Skoltech, as part of the Skoltech NGP program (theory) and National Science Foundation Grant No. DMR-1265162 (material growth).
Open access: yes (repository)