Large response of charge stripes to uniaxial stress in $\textrm{La}_{1.475}\textrm{Nd}_{0.4}\textrm{Sr}_{0.125}\textrm{Cu}\textrm{O}_{4}$
T. J. Boyle, M. Walker, A. Ruiz, E. Schierle, Z. Zhao, F. Boschini, R. Sutarto, T. D. Boyko, W. Moore, N. Tamura, F. He, E. Weschke, A. Gozar, W. Peng, A. C. Ko… 展开作者
T. J. Boyle, M. Walker, A. Ruiz, E. Schierle, Z. Zhao, F. Boschini, R. Sutarto, T. D. Boyko, W. Moore, N. Tamura, F. He, E. Weschke, A. Gozar, W. Peng, A. C. Komarek, A. Damascelli, C. Schüßler-Langeheine, A. Frano, E. H. da Silva Neto, S. Blanco-Canosa
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6 pages, 3 figures, Supplemental material available upon request
The La-based '214' cuprates host several symmetry breaking phases including superconductivity, charge and spin order in the form of stripes, and a structural othorhombic-to-tetragonal phase transition. Therefore, these materials are an ideal system to study the effects of uniaxial stress onto the various correlations that pervade the cuprate phase diagram. We report resonant x-ray scattering experiments on $\textrm{La}_{1.475}\textrm{Nd}_{0.4}\textrm{Sr}_{0.125}\textrm{Cu}\textrm{O}_{4}$ (LNSCO-125) that reveal a significant response of charge stripes to uniaxial tensile-stress of $\sim$ 0.1 GPa. These effects include a reduction of the onset temperature of stripes by $\sim$ 50 K, a 29 K reduction of the low-temperature orthorhombic-to-tetragonal transition, competition between charge order and superconductivity, and a preference for stripes to form along the direction of applied stress. Altogether, we observe a dramatic response of the electronic properties of LNSCO-125 to a modest amount of uniaxial stress.
Static stripe order is detrimental to superconductivity. Yet, it has been proposed that transverse stripe fluctuations may enhance the inter-stripe Josephson coupling and thus promote superconductivity. Direct experimental studies of stripe dynamics, however, remain difficult. From a strong-coupling perspective, transverse stripe fluctuations are realized in the form of dynamic "kinks" -- sideways shifting stripe sections. Here, we show how modest uniaxial pressure tuning reorganizes directional kink alignment. Our starting point is La$_{1.88}$Sr$_{0.12}$CuO$_4$, where transverse kink ordering…
The effect of uniaxial pressure on superconductivity was examined for a high-Tc cuprate La1.64Eu0.2Sr0.16CuO4, which is located at the boundary between the superconducting and stripe phases. We found remarkably large anisotropy of the uniaxial pressure effect not only between the in-plane and out-of-plane pressures but also within the CuO2-plane. When the pressure is applied along the tetragonal [110] direction, we found the largest pressure effect ever observed in cuprates, dTc/dP - 2.5 K/kbar, while the change of Tc was not appreciable when applied along [100]. This substantial in-plane anis…
Unidirectional spin and charge density wave order in the cuprates is known to compete with superconductivity. In the stripe order (La,M)$_2$CuO$_4$ family of cuprates, spin and charge order occur as unidirectional order that can be stabilized by symmetry breaking structural distortions, such as the low temperature tetragonal (LTT) phase. Here we examine the interplay between structure and the formation of charge density wave (CDW) order in the LTT phase of La$_{1.475}$Nd$_{0.4}$Sr$_{0.125}$CuO$_4$ by applying uniaxial stress to distort the structure and influence the formation of CDW order. Us…
We report muon spin rotation and magnetic susceptibility experiments on in-plane stress effects on the static spin-stripe order and superconductivity in the cuprate system La2-xBaxCuO4 with x = 0.115. An extremely low uniaxial stress of 0.1 GPa induces a substantial decrease in the magnetic volume fraction and a dramatic rise in the onset of 3D superconductivity, from 10 to 32 K; however, the onset of at-least-2D superconductivity is much less sensitive to stress. These results show not only that large-volume-fraction spin-stripe order is anti-correlated with 3D superconducting (SC) coherence,…
The coupling of spin, charge and lattice degrees of freedom results in the emergence of novel states of matter across many classes of strongly correlated electron materials. A model example is unconventional superconductivity, which is widely believed to arise from the coupling of electrons via spin excitations. In cuprate high-temperature superconductors, the interplay of charge and spin degrees of freedom is also reflected in a zoo of charge and spin-density wave orders that are intertwined with superconductivity. A key question is whether the different types of density waves merely coexist …
The stripe state at 1/8 Ba doping hosts optimal superconductivity in La-214 cuprates under low in-plane stress
PSI Center for Neutron and Muon Sciences CNM（瑞士保罗谢勒研究所中子与μ子科学中心）；Sophia University（上智大学）；Technische Universität Dresden（德累斯顿工业大学）；PSI Center for Scientific Computing, Theory and Data（瑞士保罗谢勒研究所科学计算、理论与数据中心）
We report simulation results of skyrmions on fluctuating 2D lattices, where the vertices ${\bf r}_i (\in {\bf R}^3)$ are treated as a dynamical variable and, hence, there is no crystalline structure. On the fluctuating surfaces, an external magnetic field perpendicular to the surface, Dzyaloshinskii-Moriya and ferromagnetic interactions are assumed in addition to the Helfrich-Polyakov Hamiltonian for membranes. The surface (or frame) tension $τ$ is calculated under both isotropic and uniaxial strain conditions, and this calculation clarifies a non-trivial dependence of $τ$ on the skyrmion, str…
Suppression of superconductivity in favour of a striped phase, and its coincidence with a structural transition from a low-temperature orthorhombic (LTO) to a low-temperature tetragonal (LTT) phase, is a ubiquitous feature of hole-doped lanthanum cuprates. We study the effect of anisotropic strain on this transition using density-functional theory on both La$_2$CuO$_4$ and the recently-synthesised surrogate La$_2$MgO$_4$ to decouple electronic and structural effects. Strikingly, we find that compressive strain applied diagonally to the in-plane metal-oxygen bonds dramatically stabilises the LT…
Recent STM experiments reveal niobium diselenide to support domains of striped (1Q) charge order side-by-side with its better-known triangular (3Q) phase, suggesting that small variations in local strain may induce a quantum phase transition between the two. We use a theoretical model of the charge order in NbSe$_2$, based on a strong momentum- and orbital-dependent electron-phonon coupling, to study the effect of uniaxial strain. We find that as little as $0.1\%$ anisotropic shift in phonon energies breaks the threefold symmetry in favor of a 1Q state, in agreement with the experimental resul…
The effects of electron correlation in the quasi-two-dimensional organic conductor α-(BEDT-TTF)2I3 are investigated theoretically by using an extended Hubbard model with on-site and nearest-neighbor Coulomb interactions. A variational Monte Carlo method is applied to study its ground-state properties. We show that there appears a nonmagnetic horizontal-stripe charge order in which nearest-neighbor correlation functions indicate a tendency toward a spin-singlet formation on the bonds with large transfer integrals along the charge-rich stripe. Under uniaxial pressure, a first-order transition fr…
Lower thermal stability due to thinning often leads to unprecedented hidden phases in low-dimensional materials. Such hidden phases can coexist or compete with preexisting electronic phases. We investigate hidden phases observed in atomically thin (6-8 layers) 1T-TaS$_2$ with scanning tunneling microscopy. First, we can electrically induce a hidden stripe phase at room temperature. Such a uniaxial stripe phase has three equivalent orientations by breaking three-fold symmetry of 1T-TaS$_2$. We also reveal that the hidden stripe phase coexists with nearly commensurate charge-density-wave phase. …
Crossover and Changeover in Spin-1 Kitaev-$Γ$ Chain with Uniaxial Single-ion Anisotropy
Nanjing University of Aeronautics and Astronautics（南京航空航天大学）；Beijing Computational Science Research Center（北京计算科学研究中心）；Nankai University（南开大学）；Beijing University of Posts and Telecommunications（北京邮电大学）；Lanzhou University（兰州大学）；Zhejiang University（浙江大学）
Weyl semimetals in three-dimensional crystals provide the paradigm example of topologically protected band nodes. It is usually taken for granted that a pair of colliding Weyl points annihilate whenever they carry opposite chiral charge. In a stark contrast, here we report that Weyl points in systems symmetric under the composition of time-reversal with a $π$-rotation are characterized by a non-Abelian topological invariant. The topological charges of the Weyl points are transformed via braid phase factors which arise upon exchange inside symmetric planes of the reciprocal momentum space. We e…
In this paper, we show that the theory of high $T_c$ superconductivity based on a microscopic model with $d$-density wave (DDW) scenario in the pseudogap phase is able to reproduce some of the most important features of the recent experimentally discovered hidden charge order in several families of Cuprates. In particular, by computing and comparing energies of charge orders of different modulation directions derived from a full microscopic theory with $d$-density wave scenario, the axial charge order $ϕ_{X(Y)}$ with wavevector $\mathbf{Q}=(Q_0,0)((0,Q_0))$ is shown to be unambiguously energet…
