Observation of inversion, hysteresis, and collapse of spin in optically trapped polariton condensates

• Published in: Physical Review B
• Main Authors: del Valle-Inclan Redondo, Yago, Sigurdsson, Helgi, Ohadi, Hamid, Shelykh, Ivan A., Rubo, Yuri G., Hatzopoulos, Zacharias, Savvidis, Pavlos G., Baumberg, Jeremy J.
• Other Authors: University of St Andrews. School of Physics and Astronomy
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: QC Physics; TK Electrical engineering. Electronics Nuclear engineering; NDAS; QC; TK; Iceland
• Online Access: http://hdl.handle.net/10023/17716; https://doi.org/10.1103/PhysRevB.99.165311

We acknowledge Grants No. EPSRC EP/L027151/1 and No. ERC LINASS 320503, Leverhulme Trust Grant No. VP1-2013-011 and bilateral Greece-Russia ‘Polisimulator’ project co-financed by Greece and the EU Regional Development Fund. H.S. acknowledges support by the Research Fund of the University of Iceland, The Icelandic Research Fund, Grant No. 163082-051. The work of IAS on theoretical analysis of the discovered effects was supported by the Ministry of Education and Science of Russian Federation, Projects 14.Y26.31.0015 and 3.2614.2017/4.6. Y.G.R. acknowledges support from CONACYT (Mexico) under Grant No. 251808. The work of PS on structure growth and characterization was supported by Russian Science Foundation, Grant No. 19-72-20120. The spin and intensity of optically trapped polariton condensates are studied under steady-state elliptically polarized nonresonant pumping. Three distinct effects are observed: (1) spin inversion where condensation occurs in the opposite handedness from the pump, (2) spin and intensity hysteresis as the pump power is scanned, and (3) a sharp “spin collapse” transition in the condensate spin as a function of the pump ellipticity. We show these effects are strongly dependent on trap size and sample position and are linked to small counterintuitive energy differences between the condensate spin components. Our results, which fail to be fully described within the commonly used nonlinear equations for polariton condensates, show that a more accurate microscopic picture is needed to unify these phenomena in a two-dimensional condensate theory. Publisher PDF Peer reviewed