This paper reviews the current progress on searching the Kitaev spin liquid state in 3d electron systems. Honeycomb cobaltates were recently proposed as promising candidates to realize the Kitaev spin liquid state, due to the more localized wavefunctions of 3d ions compared with that of 4d and 5d ions, and also the easy tunability of the exchange Hamiltonian in favor of Kitaev interaction. Several key parameters that have large impacts on the exchange constants, such as the charge-transfer gap and the trigonal crystal field, are identified and discussed. Specifically, tuning crystal field effect by means of strain or pressure is emphasized as an efficient phase control method driving the magnetically ordered cobaltates into the spin liquid state. Experimental results suggesting the existence of strong Kitaev interactions in layered honeycomb cobaltates are discussed. Finally, the future research directions are briefly outlined.

中文翻译：

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迈向 3d 过渡金属化合物中的 Kitaev 旋转液体

本文回顾了目前在 3 中搜索 Kitaev 自旋液态的进展d电子系统。最近提出蜂窝钴酸盐作为实现基塔耶夫自旋液态的有希望的候选者，因为3d离子与4d和5d离子，以及交换哈密顿量的易调谐性，有利于基塔耶夫相互作用。确定并讨论了对交换常数有很大影响的几个关键参数，例如电荷转移间隙和三角晶体场。具体而言，强调通过应变或压力调节晶体场效应作为驱动磁性有序钴酸盐进入自旋液态的有效相位控制方法。讨论了表明层状蜂窝钴酸盐中存在强 Kitaev 相互作用的实验结果。最后，简要概述了未来的研究方向。