Raman fingerprints of fractionalized Majorana excitations in the honeycomb iridate Ag3LiIr2O6

Abstract

We report low-temperature (down to ∼5 K) Raman signatures of the recently discovered intercalated honeycomb magnet Ag 3 LiIr 2 O 6 , a putative Kitaev quantum spin liquid (QSL) candidate. The Kitaev QSL is predicted to host Majorana fermions as its emergent elementary excitations through a thermal fractionalization of entangled spins S = 1/2. We observe evidence of this fractionalization in the low-energy magnetic continuum whose temperature evolution harbors signatures of the predicted Fermi statistics obeyed by the itinerant Majorana quasiparticles. The magnetic Raman susceptibility evinces a crossover from the conventional to a Kitaev paramagnetic state below the temperature of ∼80 K. Additionally, the development of the Fano asymmetry in the low-frequency phonon mode and the enhancement of integrated Raman susceptibilities below the crossover temperature signifies prominent coupling between the vibrational and Majorana fermionic excitations.

Data-Driven High-Throughput Screening and Experimental Realization of Ag2B(IV)B′(VI)O6 under Negative Chemical-Pressure

“…17 The Ag + cation has similar chemical characteristics with alkali metal cations like Li + and Na + . This resemblance often facilitates their interchangeable modification as seen in as the preparation of Ag 3 LiIr 2 O 6 23,24 and AgCoO 2 25 from their alkalimetal precursors. Alkali metal-based DPs have been extensively and intensively investigated to date, driven by their varied physical and chemical properties.…”

“…The Ag + cation has similar chemical characteristics with alkali metal cations like Li + and Na + . This resemblance often facilitates their interchangeable modification as seen in as the preparation of Ag 3 LiIr 2 O 6 , and AgCoO 2 from their alkali-metal precursors. Alkali metal-based DPs have been extensively and intensively investigated to date, driven by their varied physical and chemical properties. ,− In contrast, Ag-based DPs have not been thoroughly explored, resulting in a notable deficiency and an area that requires further research to understand their structures and properties.…”