论文标题
通过沮丧的莫特绝缘子的相图来追逐自旋隙
Chasing the spin gap through the phase diagram of a frustrated Mott insulator
论文作者
论文摘要
对纠缠的旋转激发的追求激发了对沮丧的磁系统的深入研究。在近二十年的时间里，三角晶格的莫特绝缘子$κ$ - （bedt-ttf）$ _ 2 $ cu $ _2 $（CN）$ _ 3 $一直是$ Gapless $ gapless $ Quantum spin液体的最热候选者。然而，最近，随着电子自旋呼声（ESR）研究推出了自旋差距，这种情况被推翻，呼吁重新评估磁接地态。在这里，我们通过超高分辨率应变调整通过Mott Transition实现了这一自旋差相的精确映射。我们的运输实验表明，电荷定位的重新进入$ t^{\ star} = 6 $ k与间隙大小相关的30-50 k。绝缘剂 - 金属边界的负斜率，$ dt^{\ star}/dp <0 $，证明了自旋平面基地的低入性质。 By tuning the enigmatic '6 K anomaly' through the phase diagram of $κ$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$, we identify it as the transition to a valence-bond-solid phase, with typical magnetic and structural fingerprints, that persists at $T\rightarrow 0$ until unconventional superconductivity and metallic transport扩散。
The quest for entangled spin excitations has stimulated intense research on frustrated magnetic systems. For almost two decades, the triangular-lattice Mott insulator $κ$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$ has been the hottest candidate for a $gapless$ quantum spin liquid with itinerant spinons. Very recently, however, this scenario was overturned as electron-spin-resonance (ESR) studies unveiled a spin gap, calling for reevaluation of the magnetic ground state. Here we achieve a precise mapping of this spin-gapped phase through the Mott transition by ultrahigh-resolution strain tuning. Our transport experiments reveal a reentrance of charge localization below $T^{\star}=6$ K associated with a gap size of 30-50 K. The negative slope of the insulator-metal boundary, $dT^{\star}/dp<0$, evidences the low-entropy nature of the spin-singlet ground state. By tuning the enigmatic '6 K anomaly' through the phase diagram of $κ$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$, we identify it as the transition to a valence-bond-solid phase, with typical magnetic and structural fingerprints, that persists at $T\rightarrow 0$ until unconventional superconductivity and metallic transport proliferate.
