We study the electronic structure within a system of phase-decoupled one-dimensional superconductors coexisting with stripe spin and charge-density-wave order. This system has a nodal Fermi surface (Fermi arc) in the form of a hole pocket and an antinodal pseudogap. The spectral function in the antinodes is approximately particle-hole symmetric contrary to the gapped regions just outside the pocket. We find that states at the Fermi energy are extended whereas states near the pseudogap energy have localization lengths as short as the interstripe spacing. We consider pairing which has either local $d$ -wave or $s$ -wave symmetry and find similar results in both cases, consistent with the pseudogap being an effect of local pair correlations. We suggest that this state is a stripe-ordered caricature of the pseudogap phase in underdoped cuprates with coexisting spin-, charge-, and pair-density-wave correlations. Lastly, we also model a superconducting state which (1) evolves smoothly from the pseudogap state, (2) has a signature subgap peak in the density of states, and (3) has the coherent pair density concentrated to the nodal region.We study the electronic structure within a system of phase-decoupled one-dimensional superconductors coexisting with stripe spin and charge-density-wave order. This system has a nodal Fermi surface (Fermi arc) in the form of a hole pocket and an antinodal pseudogap. The spectral function in the antinodes is approximately particle-hole symmetric contrary to the gapped regions just outside the pocket. We find that states at the Fermi energy are extended whereas states near the pseudogap energy have localization lengths as short as the interstripe spacing. We consider pairing which has either local $d$-wave or $s$-wave symmetry and find similar results in both cases, consistent with the pseudogap being an effect of local pair correlations. We suggest that this state is a stripe-ordered caricature of the pseudogap phase in underdoped cuprates with coexisting spin-, charge-, and pair-density-wave correlations. Lastly, we also model a superconducting state which (1) evolves smoothly from the pseudogap state, (2) has a signature subgap peak in the density of states, and (3) has the coherent pair density concentrated to the nodal region.

arXiv:0910.0981Physical Review BJan 4, 201013 citations

Pairing in the presence of a pseudogap

Douglas J. Scalapino, Thomas Maier, Peter Staar +1 more

Bulletin of the American Physical SocietyMar 18, 20160 citations

Pairing fluctuations and an anisotropic pseudogap phenomenon in an ultracold superfluid Fermi gas with plural p -wave superfluid phases

Daisuke Inotani, Yoji Ohashi

We investigate the superfluid properties of a one-component Fermi gas with a uniaxially anisotropic $p$ -wave pairing interaction, ${U}_{x}>{U}_{y}={U}_{z}$ [where ${U}_{i}\phantom{\rule{0.28em}{0ex}}(i=x,y,z)$ is a ${p}_{i}$ -wave pairing interaction]. This type of interaction is considered to be realized in a $^{40}\mathrm{K}$ Fermi gas. Including pairing fluctuations within a strong-coupling $T$ -matrix theory, we determine the ${p}_{x}$ -wave superfluid phase transition temperature ${T}_{\mathrm{c}}^{{p}_{x}}$ , as well as the other phase transition temperature ${T}_{\mathrm{c}}^{{p}_{x}+i{p}_{y}}\phantom{\rule{0.28em}{0ex}}(<{T}_{\mathrm{c}}^{{p}_{x}})$ , below which the superfluid order parameter has the ${p}_{x}+i{p}_{y}$ -wave symmetry. In the normal state near ${T}_{\mathrm{c}}^{{p}_{x}}, {p}_{x}$ -wave pairing fluctuations are shown to induce an anisotropic pseudogap phenomenon, where a dip structure in the angle-resolved density of states around $\ensuremath{\omega}=0$ is the most remarkable in the ${p}_{x}$ direction. In the ${p}_{x}$ -wave superfluid phase $({T}_{\mathrm{c}}^{{p}_{x}+i{p}_{y}}<T\ensuremath{\le}{T}_{\mathrm{c}}^{{p}_{x}})$, while the pseudogap in the ${p}_{x}$ direction continuously changes to the superfluid gap, the pseudogap in the perpendicular direction to the ${p}_{x}$ axis is found to continue developing because of enhanced ${p}_{y}$ -wave and ${p}_{z}$ -wave pairing fluctuations around the node of the ${p}_{x}$ -wave superfluid order parameter. Since pairing fluctuations are always suppressed in the isotropic $s$ -wave superfluid state, this phenomenon is peculiar to an unconventional Fermi superfluid with a nodal superfluid order parameter. Since the $p$ -wave Fermi superfluid is the most promising non- $s$ -wave pairing state in an ultracold Fermi gas, our results would contribute to understanding how the anisotropic pairing fluctuations, as well as the existence of plural superfluid phases, affect many-body properties of this unconventional Fermi superfluid.We investigate the superfluid properties of a one-component Fermi gas with a uniaxially anisotropic $p$-wave pairing interaction, ${U}_{x}>{U}_{y}={U}_{z}$ [where ${U}_{i}\phantom{\rule{0.28em}{0ex}}(i=x,y,z)$ is a ${p}_{i}$-wave pairing interaction]. This type of interaction is considered to be realized in a $^{40}\mathrm{K}$ Fermi gas. Including pairing fluctuations within a strong-coupling $T$-matrix theory, we determine the ${p}_{x}$-wave superfluid phase transition temperature ${T}_{\mathrm{c}}^{{p}_{x}}$, as well as the other phase transition temperature ${T}_{\mathrm{c}}^{{p}_{x}+i{p}_{y}}\phantom{\rule{0.28em}{0ex}}(<{T}_{\mathrm{c}}^{{p}_{x}})$, below which the superfluid order parameter has the ${p}_{x}+i{p}_{y}$-wave symmetry. In the normal state near ${T}_{\mathrm{c}}^{{p}_{x}}, {p}_{x}$-wave pairing fluctuations are shown to induce an anisotropic pseudogap phenomenon, where a dip structure in the angle-resolved density of states around $\ensuremath{\omega}=0$ is the most remarkable in the ${p}_{x}$ direction. In the ${p}_{x}$-wave superfluid phase $({T}_{\mathrm{c}}^{{p}_{x}+i{p}_{y}}<T\ensuremath{\le}{T}_{\mathrm{c}}^{{p}_{x}})$, while the pseudogap in the ${p}_{x}$ direction continuously changes to the superfluid gap, the pseudogap in the perpendicular direction to the ${p}_{x}$ axis is found to continue developing because of enhanced ${p}_{y}$-wave and ${p}_{z}$-wave pairing fluctuations around the node of the ${p}_{x}$-wave superfluid order parameter. Since pairing fluctuations are always suppressed in the isotropic $s$-wave superfluid state, this phenomenon is peculiar to an unconventional Fermi superfluid with a nodal superfluid order parameter. Since the $p$-wave Fermi superfluid is the most promising non-$s$-wave pairing state in an ultracold Fermi gas, our results would contribute to understanding how the anisotropic pairing fluctuations, as well as the existence of plural superfluid phases, affect many-body properties of this unconventional Fermi superfluid.

arXiv:1508.06691Physical Review ADec 30, 201512 citations

Spectral properties and pseudogaps in a model withd-wave pairing symmetry

Bumsoo Kyung

A model with d-wave pairing symmetry is studied by employing a nonperturbative sum-rule approach. At low temperature the magnitude of a normal-state pseudogap shows strong $\stackrel{\ensuremath{\rightarrow}}{k}$ or angle dependence well fitted by $\mathrm{cos}2\ensuremath{\varphi}$ form. With increasing temperature, the pseudogap closes at some critical angle ${\ensuremath{\varphi}}_{c},$ and beyond this angle a single quasiparticlelike peak appears. The resulting Fermi surface is strongly temperature dependent. Both in the spectral function and the density of states, the pseudogap disappears in a manner that the spectral weight fills in the pseudogap instead of closing it with increasing temperature. All these features are qualitatively consistent with angle resolved photoemission spectroscopy for underdoped cuprates.A model with d-wave pairing symmetry is studied by employing a nonperturbative sum-rule approach. At low temperature the magnitude of a normal-state pseudogap shows strong $\stackrel{\ensuremath{\rightarrow}}{k}$ or angle dependence well fitted by $\mathrm{cos}2\ensuremath{\varphi}$ form. With increasing temperature, the pseudogap closes at some critical angle ${\ensuremath{\varphi}}_{c},$ and beyond this angle a single quasiparticlelike peak appears. The resulting Fermi surface is strongly temperature dependent. Both in the spectral function and the density of states, the pseudogap disappears in a manner that the spectral weight fills in the pseudogap instead of closing it with increasing temperature. All these features are qualitatively consistent with angle resolved photoemission spectroscopy for underdoped cuprates.

arXiv:cond-mat/0003492Physical review. B, Condensed matterDec 11, 20009 citations

Universal Pairing Symmetry

Anonymous

PhysicsFeb 23, 20120 citations

d

-wave or

s

-wave symmetry and find similar results in both cases, consistent with the pseudogap being an effect of local pair correlations. We suggest that this state is a stripe-ordered caricature of the pseudogap phase in underdoped cuprates with coexisting spin-, charge-, and pair-density-wave correlations. Lastly, we also model a superconducting state which (1) evolves smoothly from the pseudogap state, (2) has a signature subgap peak in the density of states, and (3) has the coherent pair density concentrated to the nodal region.

We investigate the superfluid properties of a one-component Fermi gas with a uniaxially anisotropic

p

-wave pairing interaction,

{U}_{x}>{U}_{y}={U}_{z}

[where

{U}_{i}\phantom{\rule{0.28em}{0ex}}(i=x,y,z)

is a

{p}_{i}

-wave pairing interaction]. This type of interaction is considered to be realized in a

^{40}\mathrm{K}

Fermi gas. Including pairing fluctuations within a strong-coupling

T

-matrix theory, we determine the

{p}_{x}

-wave superfluid phase transition temperature

{T}_{\mathrm{c}}^{{p}_{x}}

, as well as the other phase transition temperature

{T}_{\mathrm{c}}^{{p}_{x}+i{p}_{y}}\phantom{\rule{0.28em}{0ex}}(<{T}_{\mathrm{c}}^{{p}_{x}})

, below which the superfluid order parameter has the

{p}_{x}+i{p}_{y}

-wave symmetry. In the normal state near

{T}_{\mathrm{c}}^{{p}_{x}}, {p}_{x}

-wave pairing fluctuations are shown to induce an anisotropic pseudogap phenomenon, where a dip structure in the angle-resolved density of states around $\ensuremath{\omega}=0$ is the most remarkable in the

{p}_{x}

direction. In the

{p}_{x}

-wave superfluid phase $({T}_{\mathrm{c}}^{{p}_{x}+i{p}_{y}}<T\ensuremath{\le}{T}_{\mathrm{c}}^{{p}_{x}})$, while the pseudogap in the

{p}_{x}

direction continuously changes to the superfluid gap, the pseudogap in the perpendicular direction to the

{p}_{x}

axis is found to continue developing because of enhanced

{p}_{y}

-wave and

{p}_{z}

-wave pairing fluctuations around the node of the

{p}_{x}

-wave superfluid order parameter. Since pairing fluctuations are always suppressed in the isotropic

s

-wave superfluid state, this phenomenon is peculiar to an unconventional Fermi superfluid with a nodal superfluid order parameter. Since the

p

-wave Fermi superfluid is the most promising non-

s

-wave pairing state in an ultracold Fermi gas, our results would contribute to understanding how the anisotropic pairing fluctuations, as well as the existence of plural superfluid phases, affect many-body properties of this unconventional Fermi superfluid.