64 research outputs found
Quantum Oscillations from Networked Topological Interfaces in a Weyl Semimetal
Layered transition metal chalcogenides are promising hosts of electronic Weyl nodes and topological superconductivity. MoTe2 is a striking example that harbors both noncentrosymmetric Td and centrosymmetric T\u27 phases, both of which have been identified as topologically nontrivial. Applied pressure tunes the structural transition separating these phases to zero temperature, stabilizing a mixed Td–T\u27 matrix that entails a network of interfaces between the two nontrivial topological phases. Here, we show that this critical pressure range is characterized by distinct coherent quantum oscillations, indicating that the difference in topology between topologically nonvtrivial Td and T\u27 phases gives rise to an emergent electronic structure: a network of topological interfaces. A rare combination of topologically nontrivial electronic structures and locked-in transformation barriers leads to this counterintuitive situation, wherein quantum oscillations can be observed in a structurally inhomogeneous material. These results further open the possibility of stabilizing multiple topological phases coexisting with superconductivity
High-resolution Ce 3d-edge resonant photoemission study of CeNi_2
Resonant photoemission (RPES) at the Ce 3d -> 4f threshold has been performed
for alpha-like compound CeNi_2 with extremely high energy resolution (full
width at half maximum < 0.2 eV) to obtain bulk-sensitive 4f spectral weight.
The on-resonance spectrum shows a sharp resolution-limited peak near the Fermi
energy which can be assigned to the tail of the Kondo resonance. However, the
spin-orbit side band around 0.3 eV binding energy corresponding to the f_{7/2}
peak is washed out, in contrast to the RPES spectrum at the Ce 3d -> 4f RPES
threshold. This is interpreted as due to the different surface sensitivity, and
the bulk-sensitive Ce 3d -> 4f RPES spectra are found to be consistent with
other electron spectroscopy and low energy properties for alpha-like
Ce-transition metal compounds, thus resolves controversy on the interpretation
of Ce compound photoemission. The 4f spectral weight over the whole valence
band can also be fitted fairly well with the Gunnarsson-Schoenhammer
calculation of the single impurity Anderson model, although the detailed
features show some dependence on the hybridization band shape and (possibly) Ce
5d emissions.Comment: 4 pages, 3 figur
Localized Character of 4f Electrons in CeRh(x=2,3) and CeNi(x=2,5)
We have measured Ce 4f spectral weights of extremely -like
Ce-transition metal intermetallic compounds CeRh (x=2,3) and CeNi
(x=2,5) by using the {\it bulk-sensitive} resonant photoemission technique at
the Ce ()-edge. Unprecedentedly high energy resolution and
longer escape depth of photoemitted electron at this photon energy enabled us
to distinguish the sharp Kondo resonance tails at the Fermi level, which can be
well described by the Gunnarsson-Sch\"onhammer(GS) calculation based on the
Anderson Impurity Hamiltonian. On the other hand, the itinerant 4f band
description shows big discrepancies, which implies that Ce 4f electrons retain
localized characters even in extremely -like compounds.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let
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