Non-Gaussian noise in the in-plane transport of lightly doped La2−xSrxC

Abstract

A study of the in-plane resistance noise on a high quality single crystal of La1.97Sr0.03CuO4 deep inside the spin-glass phase reveals the onset of non-Gaussianity and the insensitivity of the noise to the in-plane magnetic field. The results indicate that the charge dynamics becomes increasingly slow and correlated as temperature T → 0. The analysis of the higher order noise statistics provides evidence for the existence of a collective ground state of charge clusters, which seem to coexist with charge-poor antiferromagnetic domains that are frozen at such low T .

Charge avalanches and depinning in the Coulomb glass: The role of long-range interactions

“…Early work also revealed that Coulomb interactions in disordered insulators generally contribute to the formation of an extensive number of metastable states, i.e., the formation of the Coulomb glass (CG) [6][7][8]. In subsequent work, various aspects of glassy behavior of the CG were explored theoretically [9][10][11][12][13][14][15][16][17][18] and experimentally [19][20][21][22][23][24][25][26][27][28][29][30][31].…”

Memory Effects in the Charge Response of Lightly Doped La2−x Sr x CuO4

“…3). We recall that the in-plane resistance noise spectroscopy also showed [7] that the emergence of charge glassiness in CuO 2 planes takes place at even lower T than for the out-ofplane transport.…”

“…Detailed measurements were carried out on a sample that was cut out along the main crystallographic axes and polished into a bar with dimensions of 2.10x0.44x0.42 mm 3 , suitable for direct measurements of the in-plane resistance R ab . The preparation of the electrical contacts has been described elsewhere [7]. The sample resistance was measured using the standard four-probe ac technique (typically at ~7 Hz) in the Ohmic regime, at T down to 0.05 K realized in a dilution refrigerator.…”

“…In particular, in LSCO with x=0.03, which is located in the pseudogap regime, but it does not superconduct at any T (Fig. 1 inset), resistance noise spectroscopy [6,7] shows that, deep within the SG phase at T«T SG , doped holes form a collective, glassy state of charge domains or clusters located in the CuO 2 planes. These conclusions are supported by impedance spectroscopy [8].…”

Superstripes and Complexity in High-Temperature Superconductors

“…It is known that no-linear current voltage characteristic is a sign of the transition from superconductivity to normal conduction. The results indicate that the charge dynamics become increasingly slow and correlated as temperature T→0 [89]. underdoped YBCO as a function of the corrected temperature in a magnetic field [93].…”