Abstract
The origin of the weak insulating behavior of the resistivity, i.e.
$${\rho }_{xx}\propto {\mathrm{ln}}\,(1/T)$$
ρ
x
x
∝
ln
(
1
/
T
)
, revealed when magnetic fields (
H
) suppress ...superconductivity in underdoped cuprates has been a longtime mystery. Surprisingly, the high-field behavior of the resistivity observed recently in charge- and spin-stripe-ordered La-214 cuprates suggests a metallic, as opposed to insulating, high-field normal state. Here we report the vanishing of the Hall coefficient in this field-revealed normal state for all
$$T\ <\ (2-6){T}_{{\rm{c}}}^{0}$$
T
<
(
2
−
6
)
T
c
0
, where
$${T}_{{\rm{c}}}^{0}$$
T
c
0
is the zero-field superconducting transition temperature. Our measurements demonstrate that this is a robust fundamental property of the normal state of cuprates with intertwined orders, exhibited in the previously unexplored regime of
T
and
H
. The behavior of the high-field Hall coefficient is fundamentally different from that in other cuprates such as YBa
2
Cu
3
O
6+
x
and YBa
2
Cu
4
O
8
, and may imply an approximate particle-hole symmetry that is unique to stripe-ordered cuprates. Our results highlight the important role of the competing orders in determining the normal state of cuprates.
Here, we have investigated the normal state Fermi-surface properties of the kagome superconductor CsV3Sb5 using torque magnetometry with applied fields (H) up to 35 T. The torque signal shows clear ...de Haas-van Alphen (dHvA) oscillations above 15 T. The oscillations are smooth and consist of seven distinct frequencies with values from similar to ~18 T to 2135 T. The presence of higher frequencies in CsV3Sb5 is further confirmed by carrying out additional measurements using the tunnel diode oscillator technique. All frequencies measured at different tilt angles (θ) of the field direction with respect to the c axis show a 1/cosθ dependence, implying that the Fermi surfaces corresponding to these frequencies are two dimensional (2D). The absence of dHvA oscillations at θ = 90° further supports the presence of 2D Fermi surfaces. The Berry phase (φ) determined from the Landau level fan diagram for all frequencies is similar to ~ 0.4. This value is close to the theoretical value of φ = 0.5 for a nontrivial system, which strongly supports the nontrivial topology of the Fermi surfaces of these frequencies. Several quantities characterizing the Fermi surface are calculated employing the Lifshitz-Kosevich theory. These findings are crucial for exploring the interplay between nontrivial band topology, charge-density wave, and unconventional superconductivity of CsV3Sb5.
In a two-dimensional superconducting vortex lattice, the melting from the solid to the isotropic liquid can occur via an intermediate phase that retains orientational correlations. The effect of such ...correlations on transport and their interplay with the quenched disorder remain open questions. We perform magnetotransport measurements in a wide range of temperatures and magnetic fields on a weakly pinned two-dimensional vortex system in amorphous MoGe films. While at high fields, where quenched disorder dominates, we recover the typical strong-glass behavior of a vortex liquid, at low fields the resistivity shows a clear crossover to a fragile vortex glass. Our findings, supported by numerical simulations, suggest that this is a signature of heterogeneous dynamics that arises from the presence of orientational correlations.
Appl. Phys. Lett. 118, 224104 (2021) The dynamics of the charge-order domains has been investigated in
La$_{1.48}$Nd$_{0.4}$Sr$_{0.12}$CuO$_{4}$, a prototypical stripe-ordered
cuprate, using pulsed ...current injection. We first identify the regime in which
nonthermal effects dominate over simple Joule heating, and then demonstrate
that, for small enough perturbation, pulsed current injection allows access to
nonthermally-induced resistive metastable states. The results are consistent
with pinning of the fluctuating charge order, with fluctuations being most
pronounced at the charge-order onset temperature. The nonequilibrium effects
are revealed only when the transition is approached from the charge-ordered
phase. Our experiment establishes pulsed current injection as a viable and
effective method for probing the charge-order dynamics in various other
materials.
The origin of the weak insulating behavior of the resistivity, i.e. \(\rho_{xx}\propto\ln(1/T)\), revealed when magnetic fields (\(H\)) suppress superconductivity in underdoped cuprates has been a ...longtime mystery. Surprisingly, the high-field behavior of the resistivity observed recently in charge- and spin-stripe-ordered La-214 cuprates suggests a metallic, as opposed to insulating, high-field normal state. Here we report the vanishing of the Hall coefficient in this field-revealed normal state for all \(T<(2-6)T_{\mathrm{c}}^{0}\), where \(T_{\mathrm{c}}^{0}\) is the zero-field superconducting transition temperature. Our measurements demonstrate that this is a robust fundamental property of the normal state of cuprates with intertwined orders, exhibited in the previously unexplored regime of \(T\) and \(H\). The behavior of the high-field Hall coefficient is fundamentally different from that in other cuprates such as YBa\(_2\)Cu\(_3\)O\(_{6+x}\) and YBa\(_2\)Cu\(_4\)O\(_{8}\), and may imply an approximate particle-hole symmetry that is unique to stripe-ordered cuprates. Our results highlight the important role of the competing orders in determining the normal state of cuprates.
In two-dimensional (2D) systems, the melting from a solid to an isotropic liquid can occur via an intermediate phase that retains orientational order. However, in 2D superconducting vortex lattices, ...the effect of orientational correlations on transport, and their interplay with disorder remain open questions. Here we study a 2D weakly pinned vortex system in amorphous MoGe films over an extensive range of temperatures (\(\bm{T}\)) and perpendicular magnetic fields (\(\bm{H}\)) using linear and nonlinear transport measurements. We find that, at low fields, the resistivity obeys the Vogel-Fulcher-Tamman (VFT) form, \(\bm{\rho(T)\propto\exp-{W}(H)/(T-T_0(H))}\), characteristic of fragile glasses. As \(\bm{H}\) increases, \(\bm{T_0(H)}\) is suppressed to zero, and a standard vortex liquid behavior consistent with a \(\bm{T=0}\) superconducting transition is observed. Our findings, supported also by simulations, suggest that the presence of orientational correlations gives rise to a heterogeneous dynamics responsible for the VFT behavior. The effects of quenched disorder become dominant at high \(\bm{H}\), where a crossover to a strong-glass behavior is observed. This is a new insight into the dynamics of melting in 2D systems with competing orders.
The dynamics of the charge-order domains has been investigated in La\(_{1.48}\)Nd\(_{0.4}\)Sr\(_{0.12}\)CuO\(_{4}\), a prototypical stripe-ordered cuprate, using pulsed current injection. We first ...identify the regime in which nonthermal effects dominate over simple Joule heating, and then demonstrate that, for small enough perturbation, pulsed current injection allows access to nonthermally-induced resistive metastable states. The results are consistent with pinning of the fluctuating charge order, with fluctuations being most pronounced at the charge-order onset temperature. The nonequilibrium effects are revealed only when the transition is approached from the charge-ordered phase. Our experiment establishes pulsed current injection as a viable and effective method for probing the charge-order dynamics in various other materials.
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