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Research Highlight

CsYbSe2 is a candidate quantum spin liquid

Topic:
Crystal structure of CsYbSe2
(a) Crystal structure of CsYbSe2 depicting perfect frustrated rare-earth triangular lattice (Yb in red, Se in green), and distance of the nearest neighbor (dnn). (b) Low-energy neutron spin excitation spectrum of CsYbSe2 at 2 K confirming the absence of a long- range magnetic order.

PI: Athena Sefat

The magnetic properties of two-dimensional (2D) crystalline CsYbSe2, characterized using a combination of measurements of magnetization, heat capacity and inelastic neutron scattering (INS), indicate the possible quantum spin liquid (QSL) ground state for this material. The finding of QSL behavior in CsYbSe2 could inform applications in quantum communication and computation.

The QSL state is an important topic in frustrated magnetism, where highly entangled spins prevent the breaking of any symmetry, even at a temperature of 0 K. Recently, 2D triangular lattices made of rare earths have attracted attention in the search for QSL candidates. Here, magnetization, heat capacity and INS measurements reveal no long-range magnetic order down to 0.4 K at zero magnetic field in CsYbSe2. Magnetic field perturbs the QSL ground state and induces long-range order characteristic of a magnetically frustrated 2D triangular lattice. Strong spin fluctuations were revealed by the broad peak in heat capacity and highly damped INS magnetic excitation. Experimental magnetic field–temperature (H-T) phase diagram of CsYbSe2, shows the extent of magnetism in this Yb-based QSL candidate.Related Publication:

Related publication:

J. Xing, L. D. Sanjeewa, J. Kim, G. R. Stewart, A. Podlesnyak, and A. S. Sefat, Field-induced magnetic transition and spin fluctuations in the quantum spin-liquid candidate CsYbSe2, Phys. Rev. B 100, 220407(R) (2019).