Evolution of charge order topology across a magnetic phase transition in cuprate superconductors

Abstract

Charge order is now accepted as an integral constituent of cuprate high-temperature superconductors, one that is intimately related to other instabilities in the phase diagram including antiferromagnetism and superconductivity [1][2][3][4][5][6][7][8][9][10][11]. Unlike nesting-induced Peierls-like density waves, the charge correlations in the CuO 2 planes have been predicted to display a rich momentum space topology depending on the detailed fermiology of the system [12][13][14][15][16][17][18][19]. However, to date charge order has only been observed along the high-symmetry Cu-O bond directions. Here, using resonant soft X-ray scattering, we investigate the evolution of the full momentum space topology of charge correlations in T -Ln 2 CuO 4 (Ln=Nd, Pr) as a function of intrinsic electron doping. We report that, upon electron doping the parent Mott insulator, charge correlations first emerge in a hitherto-unobserved form, with full (C inf ) rotational symmetry in momentum-space. At higher doping levels, the orientation of charge correlations is sharply locked to the Cu-O bond high-symmetry directions, restoring a more conventional bidirectional charge order with enhanced correlation lengths. Through charge susceptibility calculations, we closely reproduce the drastic evolution in the topology of charge correlations across an antiferromagnetic quantum phase transition, highlighting the interplay between spin and charge degrees of freedom in electron-doped cuprates. Finally, using the established link between charge correlations and the underlying fermiology, we propose a revised phase diagram of T -Ln 2 CuO 4 with a superconducting region extending toward the Mott

Distinction between pristine and disorder-perturbed charge density waves in ZrTe3

“…Under our interpretation of the broad peak as arising from FOs, it follows that upon cooling in the range T LO < T < T CDW , the lattice rapidly deforms around impurities and defects due to the local presence of FOs, which in turn enhances the disorder scattering potential and gives rise to stronger FOs. The strong momentum (k and q) dependence of such feedback mechanism 34 may explain why the FO signals materialize in the form of a reciprocal-space peak, rather than a contour 17 , as Kohn anomalies that require electron-phonon coupling also commonly exist only in highly restricted momentum regions 6,37 . Below T LO , long-range CDWs form on top of the deformed lattice, which then suppresses the disorder scattering and lead to a decrease of the broad peak.…”

“…On the other hand, even though long-range CDWs can be stabilized in the cuprates by a variety of external fields 7-9 , the threedimensional (3D) ordering propagation vector is at odds with that of the Kohn anomalies in the zero-field condition 6,9 . In contrast, the zero-field charge correlations are often found to be short ranged [10][11][12][13] and coexisting with a rather inhomogeneous electronic background [13][14][15][16][17] . It is, therefore, of primary interest to elucidate the role of disorder during the incipience of the CDWs.…”

“…It is, therefore, of primary interest to elucidate the role of disorder during the incipience of the CDWs. In fact, it has been proposed that band structure effects [18][19][20][21] , namely Friedel oscillations (FOs) seeded by impurities and quenched disorder, could produce experimental signatures that look similar to genuine CDWs 17,19,20,22 . Establishing an experimental methodology to characterize CDWs under the influence of disorder and elucidate their possible relation to FOs is hence important, but this is largely an outstanding task even in prototypical CDW materials.…”

Control of dopant crystallinity in electrochemically treated cuprate thin films

“…2c remains an open question of this work. Although we are not able to unambiguously identify a microscopic model associated with the reduced orientational order, we wish to draw the reader's attention to a recent report 30 in which charge ordering in electron doped T'-(Nd,Pr) 2 CuO 4 thin films results in a planar diffraction ring while the structural crystallinity of the films is preserved. The case of electron doped T'-(Nd,Pr) 2 CuO 4 thin films presents an intriguing analog to our results and raises the question as to whether the reduced orientational order observed in electrochemically doped La 2 CuO 4+y might be connected to a related Fermi-surface-dependent chargeordering phenomenon.…”

Descent in Symmetry during Solid State Transitions and Other Anomalies in Mixed Valence Compounds A&lt;sub&gt;x&lt;/sub&gt;M&lt;sub&gt;x&lt;/sub&gt;&lt;sup style=&quot;margin-left:-10px;&quot;&gt;Ⅱ&lt;/sup&gt;M&lt;sub&gt;1-x&lt;/sub&gt;&lt;sup style=&quot;margin-left:-16px;&quot;&gt;Ⅲ&lt;/sup&gt;F&lt;sub&gt;3&lt;/sub&gt; (A = K, Rb, Cs; M = V, Cr; x = 0.0 - 1.0)

“…Descent in symmetry in oxygen-containing perovskites was reviewed by Goodenough [1] decades before the ceramic superconductors La 2−x CuO 4 [2] and YBaCuO 7−x [3] were discovered within that family [4]. A recent article describes how charge ordering in lanthanide cuprates is related to unusual collective behavior, such as antiferromagnetism and superconductivity [5].…”