A5065217670- Physics of Superconductivity and Magnetism
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum, superfluid, helium dynamics
- Rare-earth and actinide compounds
- Quantum and electron transport phenomena
- Iron-based superconductors research
- Advanced Condensed Matter Physics
- Atomic and Subatomic Physics Research
- Magnetic and transport properties of perovskites and related materials
- High-pressure geophysics and materials
- Advanced NMR Techniques and Applications
- Nuclear physics research studies
- Theoretical and Computational Physics
- Quantum many-body systems
- Inorganic Chemistry and Materials
- Advanced Thermodynamics and Statistical Mechanics
- Strong Light-Matter Interactions
- Superconducting Materials and Applications
- Algebraic structures and combinatorial models
- Nuclear Physics and Applications
- Quantum Information and Cryptography
- Quantum chaos and dynamical systems
- Spectral Theory in Mathematical Physics
- Intermetallics and Advanced Alloy Properties
- Magnetism in coordination complexes
Kent State University
2012-2023
Carnegie Mellon University
2013
Rutgers, The State University of New Jersey
1988-1990
University of Illinois Urbana-Champaign
1985-1989
Stony Brook University
1983-1987
State University of New York
1983-1987
Exact solutions of the low-T multicomponent transport equations are adapted to spin-polarized $^{3}\mathrm{He}$ calculate viscosity and thermal conductivity. The longitudinal interactions Bedell Sanchez-Castro an assumption on spin-flip interaction used obtain scattering rates. coefficients initially decrease with polarization, then pass through a minimum rapid rise. key effects can be mostly attributed changes in singlet contributions. Effects sound attenuation also discussed.
Abstract The discovery of superconductivity in hole-doped infinite layer nickelates, R NiO 2 ( = Nd, Pr, La) has resulted sustained interest the field. A definitive picture low-energy many-body states not yet emerged. Here we provide insights into physics, based on our embedded dynamical mean-field theory calculations, and propose a correlation U )-temperature T ) phase diagram. key features are low- Fermi liquid (FL) phase, high- Curie-Weiss regime, an antiferromagnetic narrow U-T region....
A simple one-component version of Fermi-liquid theory is applied to measurements the specific heat U${\mathrm{Pt}}_{3}$ and shown suggest that an odd-parity superconductor purely electronic origin. The calculated transition temperature as a function pressure found be in quantitative agreement with experiment.
It is shown that strongly interacting Fermi systems, such as $^{3}\mathrm{He}$, transition metals, and the heavy-fermion systems can be consistently described within ``induced''-interaction Fermi-liquid formalism. The general limiting features of model are considered. In agreement with Gutzwiller (half-filled case) solution to Hubbard model, there a localization excitations ${F}_{0}^{s}$ ${F}_{1}^{s}$\ensuremath{\rightarrow}\ensuremath{\infty}. Some large ${m}^{\mathrm{*}}$ originate from...
Starting from the Landau kinetic equation, we derive exact expressions for transport coefficients of a multicomponent Fermi liquid. We consider arbitrary ratios momenta and effective masses, completely general scattering rates. As specific examples evaluate thermal conductivity, shear viscosity, diffusion system, give further details two-component case.
The Landau theory of Fermi liquids is extended to include spin-orbit coupling. After constructing the general form quasiparticle interaction (which allows coupling), forward-scattering sum rules, static properties such as sound velocity and magnetic susceptibility, stability conditions are derived. Some possible applications this considered.
In the diverse world of NAND flash applications, higher storage capacity is not only imperative. Increasingly, performance a differentiating factor and also way creating new markets or expanding existing markets. While conventional memory uses, for actual operations, every other cell along selected word line (WL) [1], this design simultaneously exercises them all. A improvement at least 100% derived from all-bitline (ABL) architecture relative to chips. Additional techniques push even levels.
The fluctuation specific heat of layered superconductors in zero and finite magnetic fields above the transition temperature is studied Ginzburg-Landau (GL) scheme. dimensional crossover behavior explored. Estimates consequences for experiments are presented $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$. effect including quartic order-parameter term GL free energy investigated case.
The Fermi-liquid parameters for heavy-fermion systems are calculated. spin fluctuations (${F}_{0}^{a}$) renormalize the effective mass modestly, but significantly affect triplet scattering amplitude; consequently, p-wave pairing occurs. Additionally in extreme limit of this model, ${F}_{0}^{a}$\ensuremath{\rightarrow}-0.906 while diverges algebraically, suggesting a Mott-like localization. This is consequence finite range interactions and many-body correlations.
We perform first-principles calculations on CaFe${}_{2}$As${}_{2}$ under hydrostatic pressure. Our total-energy show that though the striped antiferromagnetic (AFM) orthorhombic (OR) phase is favored at $P=0$, a nonmagnetic collapsed tetragonal (cT) with diminished $c$ parameter for $P>0.36$ GPa, in agreement experiments. Rather than mechanical instability, this an enthalpically driven transition from higher volume OR to lower cT phase. A simple thermodynamic model provides interpretation of...
We carry out $T=0$ first-principles total energy calculations in the entire set of alkaline 122-pnictides ($A{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$; $A$ = alkaline-earth element Ca, Sr, Ba, Ra) as a function hydrostatic pressure. find multiple distinct transitions to occur, namely an enthalpic transition which zero-pressure striped antiferromagnetic orthorhombic (OR-AFM) phase becomes thermodynamically less stable than competing tetragonal (T) phase, magnetic OR-AFM loses its magnetism and...
We consider superconductivity mediated by a charge-transfer resonance (CTR) in the weak-coupling approach to three-band extended Hubbard model for copper oxide superconductors. Our effective pairing interaction contains dynamics of CTR, and local-field effects. Unlike previous work, we solve linearized Eliashberg equations on lattice while retaining full momentum dependence wave functions. find that highest ${\mathit{T}}_{\mathit{c}}$ occurs an admixture uniform s-wave states obtain...
We explore the normal-state transport properties of electrons bound to a plane by Coulomb interaction. This system can be described two types quasiparticle excitations with wave functions extended in perpendicular direction. They form overlapping subbands characterized different relaxation times due scattering centers on plane. The is dominated upper-subband contribution. find Hall coefficient, in-plane resistivity, and angle similar those high-${\mathit{T}}_{\mathit{c}}$ materials like...
We offer an explanation for the observed crossover temperature ${T}^{*}$ in in-plane resistivity ${\ensuremath{\rho}}_{\mathrm{ab}}$ of biplanar high-${T}_{c}$ cuprates. The key to our picture is existence nondegenerate and degenerate carriers possessing different quasiparticle relaxation rates. In underdoped regime change slope $d{\ensuremath{\rho}}_{\mathrm{ab}}/dT$ at results from thermal activation carriers. overdoped regime, tend become a second small Fermi energy emerges, resulting...
We present here the first calculation of linear field dependence Landau parameters in liquid $^{3}\mathrm{He}$. From we obtain splitting ${A}_{1}$ phase superfluid conclude that orientation magnetic moments paired spins are aligned along for all pressures.
We study $p$-wave pairing in a two-component Fermi system with unequal population across weak-coupling BCS to strong-coupling BEC regimes. find rich ${m}_{s}=0$ spin triplet superfluid (SF) ground state (GS) structure as function of imbalance. Under phase stability condition, the ``global'' energy minimum is given by multitude ``mixed'' SF states formed linear combinations $m=\ifmmode\pm\else\textpm\fi{}1,0$ substates $\ensuremath{\ell}=1$ orbital angular momentum state. Except for ``pure''...
Experiments on rare-earth filled skutterudites demonstrate an intriguing array of thermodynamic, transport, and superconducting properties, bring to fore theoretical challenges posed by $f$-electron systems. First-principle calculations based density functional theory its extensions for strongly correlated systems such as the Hubbard $U$ correction, provide valuable information about electronic structure that can be used understand experiments. We present a comprehensive study Fermi surface...
We consider fermions on a 2D square lattice with finite-range pairing interaction, and obtain signatures for unconventional pair-symmetry states, d(x(2)-y(2)) extended-s (s(*)), in the Bardeen-Cooper-Schrieffer-Bose-Einstein Condensation crossover region. find that fermion momentum distribution function, v(k)(2), ratio of Bogoliubov coefficients, v(k)/u(k), Fourier transform v(k)(2) are strikingly different d s(*) symmetries The chemical potential gap functions both show several interesting...
We consider inter- and intra-species pairing interactions in an asymmetrical Fermi system. Using equation of motion method, we obtain coupled mean-field equations for superfluid gap functions population densities. construct a phase diagram across BCS-BEC regimes. Due to correlations, the BCS singlet state can sustain finite polarizations, $P$. For larger $P$, find separations BEC A exists all $P$ deep regime. Our results may apply ultracold fermions, nuclear quark matter physics.
Recent experimental advances in creating stable dipolar systems, including polar molecules with large electric dipole moments, have led to vigorous theoretical activities. Here we discuss our work on homogeneous 2D bosons dipoles oriented at an angle the direction perpendicular confining plane, i.e. for non-zero tilt angles. Using Bogoliubov-de Gennes equations, obtain T=0 excitation spectrum of Bose gas, and explore instabilities varying angle, density coupling. We map out a phase diagram...