The Dirac spin liquid was proposed to be the ground state of the spin-1/2 Kagome antiferromagnets. In a magnetic field $B$, we show that the state with Fermi pocket is unstable to the Landau level (LL) state. The LL state breaks the spin rotation around the axis of the magnetic field. We find that the LL state has an in-plane 120$^{\circ}$ $q=0$ magnetization $M$ which scales with the external field $M\sim B^α$, where $α$ is an intrinsic calculable universal number of the Dirac spin liquid. We discuss the related experimental implications which can be used to detect the possible Dirac spin liquid phase in Herbertsmithite ZnCu$_3$(OH)$_6$Cl$_2$.
We show that when the electron and hole densities are unbalanced, observable nonlinear anomalous Hall effect and current-induced orbital magnetization appear at zero magnetic field in the weak charge ordering (CO) state of an organic two-dimensional Dirac fermion system, a-(BEDT-TTF)2I3. These current-induced phenomena are caused by a finite Berry curvature dipole resulting from inversion symmetry breaking and Dirac cone tilting. In the actual system, however, these effects are canceled out between different types of inversion asymmetric CO domains. To avoid the cancellation, we propose a new …
The electronic structure of weak charge-ordering (CO) state just below the critical pressure in an organic conductor α-(BEDT-TTF)_2I_3 was experimentally investigated using peak structure in the temperature dependence of interlayer magnetoresistance (MR). Based on a minimal model considering multiple Landau levels (LLs), we discuss herein the MR peak as characteristic to multilayer massless/massive Dirac fermion (DF) systems. MR measured in the weak CO state exhibited a clear MR peak, and its magnetic-field dependence was consistent with the LL behavior of a massive DF with a small gap. Result…
Orbital Selectivity and Magnetic Ordering in Fe intercalated Dirac Semimetal Bi$_2$Se$_3$
本文采用第一性原理能带结构计算方法结合动力学平均场论研究了Fe在Bi $_2$ Se $_3$范德华能隙中的嵌入效应对磁性和输运性质的影响。电子相关性和自旋轨道耦合效应的夹杂物被发现在一个插层的Bi $_2$ Se $_3$的铁磁性能的出现。此外，通过在中等密度下插入Fe，可以改变硒化铋能带结构中的狄拉克锥。伴随着新的结构效应，Fe 3 $d$轨道上的轨道选择性金属绝缘体转变的开始导致了Fe插层Bi $_2$ Se $_3$的磁相变.此外，我们还探讨了轨道间电子-电子相关性对磁有序的依赖性以及嵌入在建立新的物理性质中的作用。
Due to an uprise in the variety of candidate compounds, kagome metals have recently gained significant attention. Among other features, kagome metals host Dirac cones as a key band structure feature away from half filling, and potentially yield an exceptionally large fine structure, beyond values found in other 2D Dirac materials such as graphene. We investigate the possibility of chiral symmetry breaking in kagome metals. Based on a heuristic lattice model, we determine the critical coupling strength and the ordering pattern by means of a Schwinger-Dyson mean-field analysis. As the leading in…
Frustrated magnets with highly degenerate ground states are at the heart of hunting exotic states of matter. Recent studies in spin-orbit coupled honeycomb magnets have generated immense interest in bond-dependent interactions, appreciating a symmetric off-diagonal $Γ$ interaction which exhibits a macroscopic degeneracy in the classical limit. Here, we study a generic spin model and discover a novel chiral-spin ordering with spontaneously broken time-reversal symmetry near the dominant $Γ$ region. The chiral-spin phase is demonstrated to possess a staggered chirality relation in different subl…
The stretched diamond lattice material LiYbO2 has recently been reported to exhibit two magnetic transitions ($T_{N1} = 1.1 K$, $T_{N2} = 0.45 K$) via specific heat, magnetization, and neutron scattering measurements [Bordelon et al., Phys. Rev. B 103, 014420 (2021)]. Here we report complementary magnetic measurements down to T = 0.28 K via the local probe technique of muon spin relaxation. While we observe a rapid increase in the zero-field muon depolarization rate at $T_{N1}$, we do not observe any spontaneous muon precession for $T < T_{N1}$, which is typically associated with long-range ma…
Incommensurate Magnetic Ordering from One-Dimensional Correlated Topological Bulk States
用唯象模型计算了几种Ce基和U基f-电子巡游化合物的无公度有序波矢（CePtSn，CePdSn，CeNiSn，CeRhIn $_5$，URu $_2$ Si $_2$，CeNiAsO，CeCu $_{(6-x)}$ Au $_x$，UNi $_2$ Al $_3$，CeCuSn）以及在BSSCO、Rb $_2$、ZnBr $_4$、MnSi和原型IC系统铬金属中。这个模型是合理的多体拓扑一维（1-D）狄拉克哈密顿量后，质心变换的手征动量集定义的局部扩展的晶体布拉格平面。讨论了该模型的波动驱动的长程体态的出现的影响。
Characterizing gapped phases by smeared boundary conformal field theories: Duality in unusual ordering with spontaneously broken generalized symmetries
Motivated by the physics of spin-orbital liquids, we study a model of interacting Dirac fermions on a bilayer honeycomb lattice at half filling, featuring an explicit global SO(3)$\times$U(1) symmetry. Using large-scale auxiliary-field quantum Monte Carlo (QMC) simulations, we locate two zero-temperature phase transitions as function of increasing interaction strength. First, we observe a continuous transition from the weakly-interacting semimetal to a different semimetallic phase in which the SO(3) symmetry is spontaneously broken and where two out of three Dirac cones acquire a mass gap. The…
