High Quality Single Crystal of Kitaev Spin Liquid Candidate Material RuBr3 Synthesized under High Pressure

TL;DR

This paper reports the successful synthesis of high-quality, millimeter-sized RuBr3 single crystals under high pressure and temperature, providing a crucial platform for studying Kitaev quantum spin liquids and their emergent phenomena.

Contribution

It introduces a novel self-flux synthesis method under high pressure for producing large, high-quality RuBr3 crystals suitable for quantum spin liquid research.

Findings

Crystals exhibit well-defined cleavage planes and lustrous appearance.

Transport measurements show narrow band-gap semiconducting behavior.

Magnetic measurements reveal antiferromagnetic transition near 29-34 K.

Abstract

Kitaev quantum spin liquids have attracted significant attention in condensed matter physics over the past decade. To understand their emergent quantum phenomena, high-quality single crystals of substantial size are essential. Here, we report the synthesis of single crystals of the Kitaev quantum spin liquid candidate RuBr3, achieving millimeter-sized crystals through a self-flux method under high pressure and high temperature conditions. The crystals exhibit well-defined cleavage planes with a lustrous appearance. Transport characterizations exhibit a narrow band-gap semiconducting behavior with 0.13 eV and 0.11 eV band-gap in ab plane and along c axis, respectively. Magnetic measurement shows a transition to antiferromagnetic (AFM) state at approximately 29 K both in ab plane and along c axis. Notably, the N\'eel temperature increases to 34 K with an applied magnetic field of up to 7 T in the ab plane, but without any change along c axis. The large size and high quality of RuBr3 single crystals provide a valuable platform for investigating various interactions, particularly the Kitaev interaction, and for elucidating the intrinsic physical properties of Kitaev quantum spin liquids.