A5075549316- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Rare-earth and actinide compounds
- Magnetic properties of thin films
- Theoretical and Computational Physics
- Iron-based superconductors research
- Superconducting Materials and Applications
- Superconductivity in MgB2 and Alloys
- High-pressure geophysics and materials
- Organic and Molecular Conductors Research
- Inorganic Fluorides and Related Compounds
- Perovskite Materials and Applications
- Corporate Taxation and Avoidance
- Topological Materials and Phenomena
- Solidification and crystal growth phenomena
- Ultrasonics and Acoustic Wave Propagation
- Magnetic Properties of Alloys
- Nuclear Materials and Properties
- Metallurgical and Alloy Processes
- Acoustic Wave Resonator Technologies
- Quantum, superfluid, helium dynamics
- Advanced Chemical Physics Studies
- Solid-state spectroscopy and crystallography
- Magnetic Properties and Applications
Cornell University
2022-2025
Université de Sherbrooke
2014-2024
Laboratoire des Solides Irradiés
2024
École Polytechnique
2024
Regroupement Québécois sur les Matériaux de Pointe
2016-2023
Florida State University
2011-2013
In the quest to increase critical temperature Tc of cuprate superconductors, it is essential identify factors that limit strength superconductivity. The upper field Hc2 a fundamental measure strength, yet there no agreement on its magnitude and doping dependence in superconductors. Here we show thermal conductivity can be used directly detect cuprates YBa2Cu3Oy, YBa2Cu4O8 Tl2Ba2CuO6+δ, allowing us map out across phase diagram. It exhibits two peaks, each located at point where Fermi surface...
There is strong experimental evidence that the superconductor Sr2RuO4 has a chiral p-wave order parameter. This symmetry does not require associated gap nodes, yet specific heat, ultrasound and thermal conductivity measurements indicate presence of nodes in superconducting structure Sr2RuO4. Theoretical scenarios have been proposed to account for existence accidental or deep minima within state. To elucidate nodal gap, it essential know whether lines (or minima) are vertical (parallel...
The material $\alpha$-RuCl$_3$ has been the subject of intense scrutiny as a potential Kitaev quantum spin liquid, predicted to display Majorana fermions low energy excitations. In practice, undergoes transition state with antiferromagnetic order below temperature $T_{\rm N}$ $\approx$ 7 K, but this can be suppressed by applying an external in-plane magnetic field $H_\parallel$ = T. Whether liquid phase exists just above that is still open question, reported observation quantized thermal...
Nematicity has emerged as a key feature of cuprate superconductors, but its link to other fundamental properties such superconductivity, charge order, and the pseudogap remains unclear. Here we use measurements transport anisotropy in ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{y}$ distinguish two types nematicity. The first is associated with short-range charge-density-wave modulations doping region near $p=0.12$. It detected Nernst coefficient, not resistivity. second type prevails...
A key to understanding high-temperature superconductivity in cuprates lies the identification of competing electronic phases these materials. In YBa${}_{2}$Cu${}_{3}$O${}_{y}$, an important cuprate with distorted CuO${}_{2}$ planes, phase is characterized by charge density-wave order. New measurements indicate that order also present HgBa${}_{2}$CuO${}_{4+\ensuremath{\delta}}$, a undistorted suggesting generic property cuprates.
The heat carriers responsible for the unexpectedly large thermal Hall conductivity of cuprate Mott insulator La2CuO4 were recently shown to be phonons. However, mechanism by which phonons in cuprates acquire chirality a magnetic field is still unknown. Here, we report similar two insulators with significantly different crystal structures and orders - Nd2CuO4 Sr2CuO2Cl2 show that potential mechanisms can excluded scattering rare-earth impurities structural domains. Our comparative study...
The thermal conductivity $\kappa$ of the quasi-2D organic spin-liquid candidate EtMe$_3$Sb[Pd(dmit)$_2$]$_2$ (dmit-131) was measured at low temperatures, down to 0.07 K. We observe a vanishingly small residual linear term $\kappa_0/T$, in $\kappa/T$ vs $T$ as $T \to 0$. This shows that low-energy excitations responsible for sizeable $\gamma$ specific heat $C$, seen $C/T$ 0,$ are localized. conclude there no mobile gapless this spin liquid candidate, contrast with prior study dmit-131...
Measurements of the Seebeck effect---a voltage induced by a temperature gradient---in cuprate confirm fundamental differences in electronic states enigmatic strange metal and pseudogap phases.
Resonant ultrasound spectroscopy (RUS) is a powerful technique for measuring the full elastic tensor of given material in single experiment. Previously, this was practically limited to regularly shaped samples such as rectangular parallelepipeds, spheres, and cylinders [W. M. Visscher et al. J. Acoust. Soc. Am. 90, 2154 (1991)]. We demonstrate new method determining moduli irregularly samples, extending applicability RUS much larger set materials. apply approach recently discovered...
Measurements of the thermal Hall conductivity in hole-doped cuprates have shown that phonons acquire chirality a magnetic field both pseudogap phase and Mott insulator state. The microscopic mechanism at play is still unclear. A number theoretical proposals are being considered including skew scattering by various defects, coupling to spins, state loop-current order with appropriate symmetries, but more experimental information required constrain scenarios. Here we present our study...
Dirac material LaCuSb 2 shows anisotropic superconducting response to applied magnetic fields.
The recent detection of charge-density modulations in YBa2Cu3Oy and other cuprate superconductors raises new questions about the normal state underdoped cuprates. In one class theories, are intertwined with pairing a dual state, expected to persist up high magnetic fields as vortex liquid. support such specific heat magnetisation data on have been interpreted terms liquid persisting above vortex-melting field Hvs at T = 0. Here we report high-field measurements electrical thermal Hall...
Abstract In various so-called strange metals, electrons undergo Planckian dissipation 1,2 , a strong and anomalous scattering that grows linearly with temperature 3 in contrast to the quadratic dependence expected from standard theory of metals. some cuprates 4,5 pnictides 6 linear resistivity on magnetic field has also been considered anomalous—possibly an additional facet dissipation. Here we show cuprate metals Nd 0.4 La 1.6− x Sr CuO 4 (ref. 7 ) 2− 8 is quantitatively consistent...
Superconductors often host multiple competing and intertwined orders, such as spin charge density waves. Recent scanning tunneling microscopy measurements suggest that the heavy-fermion superconductor UTe${}_{2}$ has both Cooper pair waves (PDWs CDWs, respectively). Using high-resolution resonant ultrasound spectroscopy, authors find here no evidence for a thermodynamic phase transition to bulk CDW state, also ruling out PDW. These highlight need distinguish between surface physics in UTe${}_{2}$.
Reconstruction of the Fermi surface in cuprate YBa${}_{2}$Cu${}_{3}$O${}_{y}$ is thought to be caused by one two types charge-density waves. Identifying which responsible could help researchers understand high-temperature superconductivity that cuprates exhibit. New experiments show short-range two-dimensional waves lead reconstruction.
Five transport coefficients of the cuprate superconductor ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{CuO}}_{6+\ensuremath{\delta}}$ were measured in normal state down to low temperature, reached by applying a magnetic field (up 66 T) large enough suppress superconductivity. The electrical resistivity, Hall coefficient, thermal conductivity, Seebeck and conductivity two overdoped single crystals, with La concentration $x=0.2$ (${T}_{\mathrm{c}} =18$ K) $x=0.0$...