Two-dimensional Quantum Critical Point in Underdoped Bi $_{2}$ Sr $_{2}$ CaCu $_{2}$ O $_{8+\delta }$ Two-dimensional Quantum Critical Point in Underdoped Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$

Thomas R. Lemberger, Jie Yong, A. McCray +3 more

Bulletin of the American Physical SocietyMar 21, 20110 citations

Fragmentation of band and Fermi surface in stripe phase

M. Ya. Ovchinnikova

The mean-field study of the stripe phases of the t - t '- U Hubbard model confirms the formation of the in-gap subbands of states localized on the domain walls. For bond-aligned stripes it is shown that segments of Fermi surfaces in antinodal and nodal directions correspond to the in-gap band or to that delocalized over a whole antiferromagnet domain. This can explain the dichotomy between the corresponding quasiparticles in La 2 − x Sr x CuO 4 (LSCO) and the suppression of spectral weight in the nodal direction in underdoped LSCO. The Fermi surface changes its topology with doping. It is confirmed also that diagonal stripes can provide an insulating state at nonzero doping.The mean-field study of the stripe phases of the t - t '- U Hubbard model confirms the formation of the in-gap subbands of states localized on the domain walls. For bond-aligned stripes it is shown that segments of Fermi surfaces in antinodal and nodal directions correspond to the in-gap band or to that delocalized over a whole antiferromagnet domain. This can explain the dichotomy between the corresponding quasiparticles in La 2 − x Sr x CuO 4 (LSCO) and the suppression of spectral weight in the nodal direction in underdoped LSCO. The Fermi surface changes its topology with doping. It is confirmed also that diagonal stripes can provide an insulating state at nonzero doping.

arXiv:cond-mat/0407767Europhysics Letters (EPL)Jan 11, 20050 citations

The Fermi surface evolution in La2−xSrxCuO4

R. Citro, S. Di Matteo, M. Marinaro +1 more

Physica B Condensed MatterJun 1, 20000 citations

Kink Structure in the Quasiparticle Band of Doped Hubbard Systems

Yoshiro Kakehashi, Peter Fulde

By making use of the self-consistent projection operator method with high-momentum and high-energy resolutions, we find a kink structure in the quasiparticle excitation spectrum of the two-dimensional Hubbard model in the underdoped regime. The kink is caused by a mixing between the quasiparticle state and excitations with short-range antiferromagnetic order. We suggest that this might be the origin of the strong concentration dependence of the 'kink' found in La_{2-x}Sr_{x}CuO_{4} (x=0.03-0.07).By making use of the self-consistent projection operator method with high-momentum and high-energy resolutions, we find a kink structure in the quasiparticle excitation spectrum of the two-dimensional Hubbard model in the underdoped regime. The kink is caused by a mixing between the quasiparticle state and excitations with short-range antiferromagnetic order. We suggest that this might be the origin of the strong concentration dependence of the 'kink' found in La_{2-x}Sr_{x}CuO_{4} (x=0.03-0.07).

arXiv:cond-mat/0507564Journal of the Physical Society of JapanSep 15, 200511 citations

Quantum phase transition in overdoped La $_{2-x}$ Sr $_x$ CuO $_4$ evinced by the superfluid densityQuantum phase transition in overdoped La$_{2-x}$Sr$_x$CuO$_4$ evinced by the superfluid density

T. Schneider

The superfluid density of overdoped La $_{2-x}$ Sr $_x$ CuO $_4$ thin films of high quality have been measured with Tc (defined by the onset of the Meissner effect) from 5.1 to 41.6 K by Bosovic et al. Given this Tc the superfluid density shows no clear evidence of critical fluctuations and no indication of vortex unbinding as T->Tc. Nevertheless, the superfluid density displays the expected behavior for for a quantum phase transition (QPT) in the (3+1)D-xy universality class, rho(T=0)~Tc^2. However, this relation is also a hallmark of dirty superconductors, treated in the mean-field approximation. Here we attempt to clear out the nature of the suppression of ro(T) as Tc->0. Noting that for any finite system the continuous transition will be rounded we perform a finite size scaling analysis. It uncovers that the ro(T) data data are consistent with a finite length limited 3D-xy transition. In some films it is their thickness and in others their inhomogeneity that determines the limiting length. Having established the precondition for the occurrence of a QPT mapping on the (3+1) D-xy model, we explore the consistency with the hallmarks of this transition. In particular with the relations rho(T)/rho(0)=1-ycT/Tc, rho((0)^Tc^2, yc=alpha*Tc/ro(0), where alpha is the coefficient in rho(T)=rho(0)-alphaT as T->0. The emerging agreement with these characteristics points clearly to a quantum fluctuations induced suppression, revealing the crossover from the thermal to the quantum critical regime as Tc ->0. In the classical-quantum mapping it corresponds to a 3D to (3 + 1)D crossover.The superfluid density of overdoped La$_{2-x}$Sr$_x$CuO$_4$ thin films of high quality have been measured with Tc (defined by the onset of the Meissner effect) from 5.1 to 41.6 K by Bosovic et al. Given this Tc the superfluid density shows no clear evidence of critical fluctuations and no indication of vortex unbinding as T->Tc. Nevertheless, the superfluid density displays the expected behavior for for a quantum phase transition (QPT) in the (3+1)D-xy universality class, rho(T=0)~Tc^2. However, this relation is also a hallmark of dirty superconductors, treated in the mean-field approximation. Here we attempt to clear out the nature of the suppression of ro(T) as Tc->0. Noting that for any finite system the continuous transition will be rounded we perform a finite size scaling analysis. It uncovers that the ro(T) data data are consistent with a finite length limited 3D-xy transition. In some films it is their thickness and in others their inhomogeneity that determines the limiting length. Having established the precondition for the occurrence of a QPT mapping on the (3+1) D-xy model, we explore the consistency with the hallmarks of this transition. In particular with the relations rho(T)/rho(0)=1-ycT/Tc, rho((0)^Tc^2, yc=alpha*Tc/ro(0), where alpha is the coefficient in rho(T)=rho(0)-alphaT as T->0. The emerging agreement with these characteristics points clearly to a quantum fluctuations induced suppression, revealing the crossover from the thermal to the quantum critical regime as Tc ->0. In the classical-quantum mapping it corresponds to a 3D to (3 + 1)D crossover.

arXiv:2105.03975May 9, 20210 citations

Decoherence mechanisms at low magnetic fields in rare-earth ion-doped Y2SiO5

Charlotte Pignol, Antonio Ortu, L. Nicolas +5 more

Sep 18, 20240 citations

Zero-Magnetic-Field Phase-Decoherence Transition in Underdoped La

_{2-x}

_{x}

CuO

_{4}

Two-dimensional Quantum Critical Point in Underdoped Bi

_{2}

_{2}

CaCu

_{2}

_{8+\delta }

Quantum phase transition in overdoped La

_{2-x}

_x

CuO

_4

evinced by the superfluid density

The superfluid density of overdoped La

_{2-x}

_x

CuO

_4

thin films of high quality have been measured with Tc (defined by the onset of the Meissner effect) from 5.1 to 41.6 K by Bosovic et al. Given this Tc the superfluid density shows no clear evidence of critical fluctuations and no indication of vortex unbinding as T->Tc. Nevertheless, the superfluid density displays the expected behavior for for a quantum phase transition (QPT) in the (3+1)D-xy universality class, rho(T=0)~Tc^2. However, this relation is also a hallmark of dirty superconductors, treated in the mean-field approximation. Here we attempt to clear out the nature of the suppression of ro(T) as Tc->0. Noting that for any finite system the continuous transition will be rounded we perform a finite size scaling analysis. It uncovers that the ro(T) data data are consistent with a finite length limited 3D-xy transition. In some films it is their thickness and in others their inhomogeneity that determines the limiting length. Having established the precondition for the occurrence of a QPT mapping on the (3+1) D-xy model, we explore the consistency with the hallmarks of this transition. In particular with the relations rho(T)/rho(0)=1-ycT/Tc, rho((0)^Tc^2, yc=alpha*Tc/ro(0), where alpha is the coefficient in rho(T)=rho(0)-alphaT as T->0. The emerging agreement with these characteristics points clearly to a quantum fluctuations induced suppression, revealing the crossover from the thermal to the quantum critical regime as Tc ->0. In the classical-quantum mapping it corresponds to a 3D to (3 + 1)D crossover.