Abstract
Understanding the interplay between the inherent disorder and the correlated fluctuating-spin ground state is a key element in the search for quantum spin liquids. H
3
LiIr
2
O
6
is ...considered to be a spin liquid that is proximate to the Kitaev-limit quantum spin liquid. Its ground state shows no magnetic order or spin freezing as expected for the spin liquid state. However, hydrogen zero-point motion and stacking faults are known to be present. The resulting bond disorder has been invoked to explain the existence of unexpected low-energy spin excitations, although data interpretation remains challenging. Here, we use resonant X-ray spectroscopies to map the collective excitations in H
3
LiIr
2
O
6
and characterize its magnetic state. In the low-temperature correlated state, we reveal a broad bandwidth of magnetic excitations. The central energy and the high-energy tail of the continuum are consistent with expectations for dominant ferromagnetic Kitaev interactions between dynamically fluctuating spins. Furthermore, the absence of a momentum dependence to these excitations are consistent with disorder-induced broken translational invariance. Our low-energy data and the energy and width of the crystal field excitations support an interpretation of H
3
LiIr
2
O
6
as a disordered topological spin liquid in close proximity to bond-disordered versions of the Kitaev quantum spin liquid.
ABSTRACT
Background: The Patient Self Determination Act of 1990 mandates healthcare providers (HCP) to speak with patients about end‐of‐life preferences and advance directives (AD). HCP work with ...patients of varying cultures, and standard ADs do not address cultural differences. In order to understand various cultural beliefs, cultural sensitivity is important especially when discussing advance care planning (ACP).
Aims: Individuals from differing ethnic backgrounds are likely to turn to their traditional norms of practice when ill or treatment choices must be made. An AD that addresses varying cultural values and beliefs was sought.
Methods: A comprehensive review of the literature was conducted. Articles selected for review included qualitative and quantitative studies. The evidence was evaluated and synthesized for information related to cultural sensitivity and ADs.
Findings: Three common themes emerged related to ACP discussions and culture. Healthcare provider awareness, communication, and education concerning cultural differences and ACP assisted in meeting the needs for end‐of‐life planning in the current era of increased globalization. Education for HCP on cultural differences and how to lead discussions promoted ACP.
Implication for Practice: ADs are an essential part of health care and promote patient‐centered care. (HCP) should be able to recognize differing cultural values and beliefs in order to initiate conversations about end of life. Initiating conversations about ACP can be facilitated by using open‐ended questions that respect the values and beliefs of various cultures.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK, VSZLJ
We use x-ray spectroscopy at the Ir L3/L2 absorption edge to study powder samples of the intercalated honeycomb magnet Ag3LiIr2O6. Based on x-ray absorption and resonant inelastic x-ray scattering ...measurements, and exact diagonalization calculations including nearest-neighbor Ir-Ir electron hopping integrals, we argue that the intercalation of Ag atoms results in a delocalized electronic structure with enhanced Ir-O hybridization, departing from the local relativistic jeff = 1/2 state. We find that the relative orbital contribution to the magnetic moment is increased and the magnetization density is spatially extended and asymmetric in this hybridized state. Our results confirm the importance of metal-ligand hybridization in the magnetism of transition metal oxides and provide empirical guidance for understanding the collective magnetism in intercalated honeycomb iridates.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
To assess the incidence, risk factors, and course of acute renal failure (ARF) following bone marrow transplantation (BMT), a retrospective analysis of 272 patients receiving transplants at the Fred ...Hutchinson Cancer Research Center during 1986 was undertaken. The patients were divided into three groups: group 1, hemodialysis requiring ARF; group 2, mild renal insufficiency (doubling of serum creatinine, Scr, but no dialysis); group 3, relatively normal post-BMT renal function (no doubling of Scr). Fifty-three percent of patients at least doubled their Scr (Groups 1 and 2), and 24% required dialysis. The degree of renal functional impairment had a dramatic impact on patient mortality rates (84%, 37%, and 17% in groups 1, 2, and 3, respectively). Jaundice (bilirubin greater than or equal to 2.0 mg/dL), weight gain (greater than or equal to 2.0 kg), amphotericin B use, and a pretransplant Scr greater than or equal to 0.7 mg/dL were independently associated with the subsequent development of dialysis-requiring ARF (P less than 0.001; relative risks, 3.0 to 7.7). Neither aminoglycoside/vancomycin/cyclosporine A use nor acute graft v host disease correlated with the development of ARF. A mismatched graft was a significant risk factor for ARF by univariate but not by multivariate analysis. Within 48 hours before doubling the Scr, 63% of group 1 patients had positive blood cultures and 39% developed hypotension. Of the 26 group 1 patients who had urine Na concentrations measured, 85% had values less than or equal to 40 mEq/L. Autopsy kidney specimens provided no clear explanation for ARF in the vast majority of patients in group 1.
We report the A -site spinel NiRh2O4 is the only known realization of a spin-1 diamond lattice magnet and is predicted to host unconventional magnetic phenomena driven by frustrated nearest and ...next-nearest neighbor exchange as well as orbital degeneracy. Previous works found no sign of magnetic order but found a gapped dispersive magnetic excitation indicating a possible valence bond magnetic ground state. However, the presence of many competing low energy degrees of freedom and limited empirical microscopic constraints complicates further analysis. Here we carry out resonant inelastic x-ray scattering (RIXS), x-ray absorption spectroscopy (XAS), and inelastic neutron scattering (INS) to characterize the local electronic structure and lattice dynamics of NiRh2O4. The RIXS data can be partly described by a single-ion model for tetrahedrally coordinated Ni2+ and indicates a tetragonal distortion Δt2 = 70 meV that splits the t2 orbitals into a high energy orbital singlet and lower energy orbital doublet. We identify features of the RIXS spectra that are consistent with a Rh-Ni two-site excitation indicating strong metal-metal hybridization mediated by oxygen in NiRh2O4. We also identify signatures of electron-phonon coupling through the appearance of phonon sidebands that dress crystal field excitations. These results establish the key energy scales relevant to the magnetism in NiRh2O4 and further demonstrate that covalency and lattice dynamics play essential roles in controlling the magnetic ground states of A -site spinels.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
In this work, we use x-ray spectroscopy at the Ir L3/L2 absorption edge to study powder samples of the intercalated honeycomb magnet Ag3LiIr2O6. Based on x-ray absorption and resonant inelastic x-ray ...scattering measurements, and exact diagonalization calculations including nearest-neighbor Ir-Ir electron hopping integrals, we argue that the intercalation of Ag atoms results in a delocalized electronic structure with enhanced Ir-O hybridization, departing from the local relativistic jeff=1/2 state. We find that the relative orbital contribution to the magnetic moment is increased and the magnetization density is spatially extended and asymmetric in this hybridized state. Our results confirm the importance of metal-ligand hybridization in the magnetism of transition metal oxides and provide empirical guidance for understanding the collective magnetism in intercalated honeycomb iridates.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Nature Communications 14, 5018 (2023) In the search for realizations of Quantum Spin Liquids (QSL), it is essential
to understand the interplay between inherent disorder and the correlated
...fluctuating spin ground state. H$_3$LiIr$_2$O$_6$ is regarded as a spin liquid
proximate to the Kitaev-limit (KQSL) in which H zero-point motion and stacking
faults are known to be present. Bond disorder has been invoked to account for
the existence of unexpected low-energy spin excitations. Controversy remains
about the nature of the underlying correlated state and if any KQSL physics
survives. Here, we use resonant X-ray spectroscopies to map the collective
excitations in H$_3$LiIr$_2$O$_6$ and characterize its magnetic state. We
uncover a broad bandwidth and momentum-independent continuum of magnetic
excitations at low temperatures that are distinct from the paramagnetic state.
The center energy and high-energy tail of the continuum are consistent with
expectations for dominant ferromagnetic Kitaev interactions between dynamically
fluctuating spins. The absence of a momentum dependence to these excitations
indicates a broken translational invariance. Our data support an interpretation
of H$_3$LiIr$_2$O$_6$ as a disordered topological spin liquid in close
proximity to bond-disordered versions of the KQSL. Our results shed light on
how random disorder affects topological magnetic states and have implications
for future experimental and theoretical works toward realizing the Kitaev model
in condensed matter systems
The $A$-site spinel NiRh$_2$O$_4$ is the only known realization of a spin-1
diamond lattice magnet and is predicted to host unconventional magnetic
phenomena driven by frustrated nearest and ...next-nearest neighbor exchange as
well as orbital degeneracy. Previous works found no sign of magnetic order but
found a gapped dispersive magnetic excitation indicating a possible valence
bond magnetic ground state. However, the presence of many competing low energy
degrees of freedom and limited empirical microscopic constraints complicates
further analysis. Here, we carry out resonant inelastic x-ray scattering (RIXS)
and x-ray absorption spectroscopy (XAS) to characterize the local electronic
structure of NiRh$_2$O$_4$. The RIXS data can be partly described by a
single-ion model for tetrahedrally coordinated Ni$^{2+}$ and indicates a
tetragonal distortion $\Delta t_2\!=\!70$ meV that splits the $t_2$ orbitals
into a high energy orbital singlet and lower energy orbital doublet. We
identify features of the RIXS spectra that are consistent with a Rh-Ni two-site
excitation indicating strong metal-metal hybridization mediated by oxygen in
NiRh$_2$O$_4$. We also identify signatures of electron-phonon coupling through
the appearance of phonon sidebands that dress crystal field excitations. These
results establish the key energy scales relevant to the magnetism in
NiRh$_2$O$_4$ and further demonstrate that covalency and lattice dynamics play
essential roles in controlling the magnetic ground states of $A$-site spinels.
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