Yb delafossites: Unique exchange frustration of 4f spin- 12 moments on a perfect triangular lattice

Mesoscale interplay between phonons and crystal electric field excitations in quantum spin liquid candidate CsYbSe2

“…Quantum spin liquid candidates like a-RuCl 3 , [4][5][6][7][8][9][10][11][12] k-(BEDT-TTF) 2 Cu 2 (CN) 3 , 13 and YbMgGaO 4 14 typically exhibit geometric frustration of some sort, but there have not yet been conclusive observations of QSLs, nor are there well accepted measurement protocols for QSL order parameters. Yb delafossites 15 such as NaYbS 2 , 16,17 NaYbSe 2 , [18][19][20] NaYbO 2 , 21,22,74 CsYbSe 2 , [23][24][25][26] and KYbSe 2 27,28 -with effective spin S eff = 1/2 from Yb 3+ ions and antiferromagnetic coupling decorating 2D triangular lattices -are popular QSL candidates. Easy-plane magnetic anisotropy results in a plateau at one-third of the saturation magnetization due to strong spin fluctuations.…”

Diluting a triangular-lattice spin liquid: Synthesis and characterization of NaYb$_{1-x}$Lu$_{x}$S$_2$ single crystals

“…Note, however, that the Weiss temperatures obtained from bulk susceptibility and ESR intensity do not exactly match. The reason for such difference, being also observed in other compounds [13,[55][56][57], could be that spin correlations are probed by ESR locally at the Yb-sites in contrast to magnetic susceptibility which is a non-local and nondynamical probe.…”

“…Further Yb-based compounds such as NaYbO 2 [10,11] and NaYbSe 2 [12] were investigated soon afterwards and also found to display no magnetic order down to 50 mK. Triangular lattice Yb compounds have thus established themselves as an important class of spin-orbit-entangled spin liquids [13]. Note that the structure type of these compounds is frequently referred to as delafossite although the mineral delafossite, CuFeO 2 , features A cations in linear coordination [14].…”

Quantifying uncertainties in crystal electric field Hamiltonian fits to neutron data

“…This is unfortunate, as Yb 3+ receives much attention as an effective J = 1/2 host for quantum magnetism. In such cases it is necessary to include additional experimental information, like electron spin resonance as was done for NaYbS 2 [21],…”