Properties of the in-gap states in SmB6

Gabáni, S.; Flachbart, К.; Konovalova, E.S.; Orendáč, M.; Paderno, Yu. B.; Pavlı́k, V.; Šebek, Jiří

doi:10.1016/s0038-1098(01)00004-7

Cited by 38 publications

(38 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…is metallic-like and reveals a temperature non-activated (metallic) channel in σ(T ), which becomes dominating below about 3 K [13][14][15][16][17]. This residual conductivity can be attributed to in-gap states, which were confirmed by other probes [5,6,24,25].…”

supporting

confidence: 53%

“…Specifically for SmB 6 , a small electronic gap (∆ = 2 − 30 K) was detected by many experimental techniques, e.g. optical conductivity [4], infrared absorption [5,6], inelastic neutron scattering [7], electron tunneling [8][9][10], and electrical transport measurements [10][11][12][13][14][15][16].…”

mentioning

confidence: 99%

“…Electrical resistivity measurements of SmB 6 show a large resistivity increase at decreasing temperature below 50 K, and saturation at very high residual value ρ 0 at lowest temperatures [12][13][14][15][16]. The corresponding electrical conductivity σ(T ) = 1/ρ(T ) in the "saturation region"…”

mentioning

confidence: 99%

See 2 more Smart Citations

SmB 6 : Topological insulator or semiconductor with valence-fluctuation induced hopping transport?

Baťko

Baťková

2014

Solid State Communications

View full text Add to dashboard Cite

show abstract

supporting

confidence: 53%

mentioning

confidence: 99%

See 1 more Smart Citation

SmB 6 : Topological insulator or semiconductor with valence-fluctuation induced hopping transport?

Baťko

Baťková

2014

Solid State Communications

View full text Add to dashboard Cite

show abstract

“…(v) There seems to be an additional, broadened hump close to −3 meV, i.e., inside the hybridization gap. One may speculate that this feature is related to in-gap states seen in other measurements (19)(20)(21)(45)(46)(47). Specifically, it is observed only for T ≤ 12 K (Fig.…”

Section: Resultsmentioning

confidence: 53%

Hybridization gap and Fano resonance in SmB₆

Rößler¹,

Jang

Kim

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

127

160

View full text Add to dashboard Cite

Hybridization between conduction electrons and the strongly interacting f-electrons in rare earth or actinide compounds may result in new states of matter. Depending on the exact location of the concomitant hybridization gap with respect to the Fermi energy, a heavy fermion or an insulating ground state ensues. To study this entanglement locally, we conducted scanning tunneling microscopy and spectroscopy (STS) measurements on the "Kondo insulator" SmB 6 . The vast majority of surface areas investigated were reconstructed, but infrequently, patches of varying sizes of nonreconstructed Smor B-terminated surfaces also were found. On the smallest patches, clear indications for the hybridization gap with logarithmic temperature dependence (as expected for a Kondo system) and for intermultiplet transitions were observed. On nonreconstructed surface areas large enough for coherent cotunneling, we were able to observe clear-cut Fano resonances. Our locally resolved STS indicated considerable finite conductance on all surfaces independent of their structure, not proving but leaving open the possibility of the existence of a topologically protected surface state.M aterials with strong electron correlations continue to draw enormous attention, not only because they may give rise to fundamentally new states of matter or new phenomena but also because of the hope for advanced technological applications. Heavy fermion (HF) materials, i.e., intermetallics of certain rare earths (REs), such as Ce, Sm, and Yb, are model systems to study strong electronic correlations (1). Here, the RE-derived localized 4f states are covalently mixed with the conduction-band states and, thus, acquire a finite lifetime. The associated decay rate in relation to the energy of the localized 4f state corresponds to the valency. In an Sm-based HF system, the valence lies between 3+ (4f 5 ) and 2+ (4f 6 ), which implies a considerable amount of charge fluctuations. This usually is referred to as intermediate valence (2). In addition to the abovementioned mixing of 4f states and the conduction band, which is well described within the framework of one-electron models, a manybody interaction is operating between the 4f and conduction electrons. This "Kondo effect" (3) eventually leads to a screening of the local moments as a result of particle-hole excitations that are manifested by a narrow Abrikosov-Suhl, or Kondo, resonance at E F , the width of which is given by the single-ion Kondo temperature T K .Because of the periodic arrangement of REs in an HF intermetallic, the Kondo resonances form a weakly dispersive HF or "coherent 4f−" band, resulting in a heavy Fermi liquid state well below T K . The band interaction between the renormalized 4f and the conduction band generates a so-called hybridization gap, which opens at around T K . Under certain conditions, E F may reside inside this gap, characterizing a so-called Kondo insulator (4).SmB 6 is such a Kondo insulator, with a valence ν ∼ 2:6 (5), ν being slightly temperature dependent (6, 7). A sharp de...

show abstract

“…In the exotic scenario where there are no in-gap bulk states, it is a possibility that such surface states can play a role in pinning the Fermi energy so far from the band center [30]. Evidence for 3D bulk in-gap states is much less clear, especially since most of the relevant studies [20,22,23,31] associated the signatures of in-gap states with the metallic behavior below 2 K, which is now known to 2 be caused by the 2D surface states in the gap. The question of Fermi-level pinning remains unresolved.…”

Section: Introductionmentioning

confidence: 99%

Reduction of the low-temperature bulk gap in samarium hexaboride under high magnetic fields

Wolgast

Sun

et al. 2017

Phys. Rev. B

View full text Add to dashboard Cite

SmB 6 exhibits a small (15-20 meV) bandgap at low temperatures due to hybridized d and f electrons, a tiny (3 meV) transport activation energy (E A ) above 4 K, and surface states accessible to transport below 2 K. We study its magnetoresistance in 60-T pulsed fields between 1.5 K and 4 K. The response of the nearly T -independent surface states (which show no Shubnikov-de Haas oscillations) is distinct from that of the activated bulk. E A shrinks by 50% under fields up to 60 T. Data up to 93 T suggest that this trend continues beyond 100 T, in contrast with previous explanations. It rules out emerging theories to explain observed exotic magnetic quantum oscillations.

show abstract

Properties of the in-gap states in SmB6

Cited by 38 publications

References 19 publications

SmB 6 : Topological insulator or semiconductor with valence-fluctuation induced hopping transport?

SmB 6 : Topological insulator or semiconductor with valence-fluctuation induced hopping transport?

Hybridization gap and Fano resonance in SmB₆

Reduction of the low-temperature bulk gap in samarium hexaboride under high magnetic fields

Contact Info

Product

Resources

About

Properties of the in-gap states in SmB6

Cited by 38 publications

References 19 publications

SmB 6 : Topological insulator or semiconductor with valence-fluctuation induced hopping transport?

SmB 6 : Topological insulator or semiconductor with valence-fluctuation induced hopping transport?

Hybridization gap and Fano resonance in SmB6

Reduction of the low-temperature bulk gap in samarium hexaboride under high magnetic fields

Contact Info

Product

Resources

About

Hybridization gap and Fano resonance in SmB₆