Related papers: Dynamical Bonding Driving Mixed Valency in a Metal…
We address the long-standing mystery of the nonmagnetic insulating state of the intermediate valence compound SmB$_6$. Within a combination of the local density approximation (LDA) and an exact diagonalization (ED) of an effective discrete…
Topological insulators host spin-polarized surface states which robustly span the band gap and hold promise for novel applications. Recent theoretical predictions have suggested that topologically protected surface states may similarly span…
Recent experiments have uncovered evidence of low energy excitations in the bulk of SmB$_6$ that are perhaps associated with unconventional quasiparticles, bringing into question whether this Kondo "insulator" is truly insulating in the…
We present angle-resolved photoemission studies on the rare-earth hexaboride YbB$_6$, which has recently been predicted to be a topological Kondo insulator. Our data do not agree with the prediction and instead show that YbB$_6$ exhibits a…
Doped divalent hexaborides such as $Sr_{1-x}La_xB_6$ exhibit high \tc ferromagnetism. We isolate a degenerate pair of $2p$-orbitals of boron with two valence electrons, invoke electron correlation and Hund coupling, to suggest that the…
We use scanning tunneling microscopy to investigate the (001) surface of cleaved SmB6 Kondo insulator. Variable temperature dI/dV spectroscopy up to 60 K reveals a gap-like density of state suppression around the Fermi level, which is due…
SmB6 exhibits intermediate valence in the ground state and unusual behaviour at low temperatures. The resistivity and the Hall effect cannot be explained either by conventional sf-hybridization or by hopping transport in an impurity band.…
Pressure induced isostructural insulator to metal transition for SmS is characterised by the presence of an intermediate valence state at higher pressure which cannot be captured by the density functional theory. As a direct outcome of…
We review current theoretical and experimental efforts to identify a novel class of intermetallic 4f and 5f orbital materials in which strong interactions between itinerant and predominately localized degrees of freedom gives rise to a bulk…
Insulators occur in more than one guise, a recent finding was a class of topological insulators, which host a conducting surface juxtaposed with an insulating bulk. Here we report the observation of an unusual insulating state with an…
Recent quantum oscillation experiments on SmB$_6$ pose a paradox, for while the angular dependence of the oscillation frequencies suggest a 3D bulk Fermi surface, SmB$_6$ remains robustly insulating to very high magnetic fields. Moreover, a…
We predict that plutonium hexaboride (PuB6) is a strongly correlated topological insulator, with Pu in an intermediate valence state of Pu^2.7+ . Within the combination of dynamical mean field theory and density functional theory, we show…
SmB6 is a proposed topological Kondo insulator where the presence of topological nontriviality can be tuned by variations in the Sm valence. Experimentally, Sm valence can be changed by tuning stoichiometry of SmB6. We show that Raman…
Topological insulators are materials characterized by dissipationless, spin-polarized surface states resulting from non-trivial band topologies. Recent theoretical models and experiments suggest that SmB6 is the first topological Kondo…
We have investigated the surface states of a potential mixed-valent topological insulator SmB$_6$ based on the first principles density functional theory slab band structure analysis. We have found that metallic surface states are formed in…
SmB6 is a strongly correlated material that has been attributed as a topological insulator and a Kondo insulator. Recent studies have found the topological surface states and low temperature insulating character to be profoundly robust…
We argue that because of valence-fluctuation caused dynamical changes (fluctuations) of impurity energies in an impurity band of valence fluctuating semiconductors both occupied and unoccupied sites can be found in the impurity band above…
The true topological nature of the Kondo insulator SmB$_6$ remains to be unveiled. Our previous tunneling study not only found evidence for the existence of surface Dirac fermions, but it also uncovered that they inherently interact with…
We report the temperature-dependent three-dimensional angle-resolved photoemission spectra of the Kondo semiconductor SmB$_6$. We found a difference in the temperature dependence of the peaks at the X and $\Gamma$ points, due to…
Recent theoretical calculations and experimental results suggest that the strongly correlated material SmB$_{6}$ may be a realization of a topological Kondo insulator. We have performed an angle-resolved photoemission spectroscopy study on…