LiYbSe2: Frustrated Magnetism in a New Pyrochlore Lattice

TL;DR

LiYbSe2 is a newly discovered pyrochlore magnet exhibiting strong geometric frustration, no magnetic order down to very low temperatures, and potential for realizing quantum spin liquid states.

Contribution

This paper reports the discovery and characterization of LiYbSe2 with a novel pyrochlore lattice structure, highlighting its magnetic frustration and absence of long-range order.

Findings

No magnetic order detected above 70 mK

Magnetic correlations shift with applied field

Potential for quantum spin liquid states

Abstract

Three-dimensionally (3D) frustrated magnets generally exist in the magnetic diamond and pyrochlore lattices, in which quantum fluctuations suppress magnetic orders and generate highly entangled ground states (GS). LiYbSe2 in a previously unreported pyrochlore lattice was discovered from LiCl flux growth. Distinct from the quantum spin liquid (QSL) candidate NaYbSe2 hosting a perfect triangular lattice of Yb3+, LiYbSe2 crystallizes in the cubic pyrochlore structure with space group Fd-3m (No. 227). The Yb3+ ions in LiYbSe2 are arranged on a network of corner-sharing tetrahedra, which is particularly susceptible to geometrical frustration. According to our temperature-dependent magnetic susceptibility measurements, the dominant antiferromagnetic interaction in LiYbSe2 is expected to appear around 8 K. However, no long-range magnetic order is detected in thermomagnetic measurements above 70 mK. Specific heat measurements also show magnetic correlations shifting with applied magnetic field with a degree of missing entropy that may be related to the slight mixture of Yb3+ on the Li site. Such magnetic frustration of Yb3+ is rare in pyrochlore structures. Thus, LiYbSe2 shows promises in intrinsically realizing disordered quantum states like QSL in pyrochlore structures.