Lin Jiao

Superconducting gap structure of FeSe

The microscopic mechanism governing the zero-resistance flow of current in some iron-based, high-temperature superconducting materials is not well understood up to now. A central issue concerning the investigation of these materials is their superconducting gap symmetry and structure. Here we present a combined study of low-temperature specific heat and scanning tunnelling microscopy measurements on single crystalline FeSe. The results reveal the existence of at least two superconducting gaps which can be represented by a phenomenological two-band model. The analysis of the specific heat suggests significant anisotropy in the gap magnitude with deep gap minima. The tunneling spectra display an overall “U”-shaped gap close to the Fermi level away as well as on top of twin boundaries. These results are compatible with the anisotropic nodeless models describing superconductivity in FeSe.

Additional energy scale in SmB6 at low-temperature

Topological insulators give rise to exquisite electronic properties because of their spin-momentum locked Dirac-cone-like band structure. Recently, it has been suggested that the required opposite parities between valence and conduction band along with strong spin-orbit coupling can be realized in correlated materials. Particularly, SmB6 has been proposed as candidate material for a topological Kondo insulator. Here we observe, by utilizing scanning tunnelling microscopy and spectroscopy down to 0.35 K, several states within the hybridization gap of about ±20 meV on well characterized (001) surfaces of SmB6. The spectroscopic response to impurities and magnetic fields allows to distinguish between dominating bulk and surface contributions to these states. The surface contributions develop particularly strongly below about 7 K, which can be understood in terms of a suppressed Kondo effect at the surface. Our high-resolution data provide insight into the electronic structure of SmB6, which reconciles many current discrepancies on this compound.

Emergence of an incipient ordering mode in FeSe

The structurally simplest Fe-based superconductor FeSe with a critical temperature

Giant anomalous Hall effect in a ferromagnetic kagome-lattice semimetal

T_{c}\approx

Impurity-induced bound states inside the superconducting gap of FeSe

8.5 K displays a breaking of the four-fold rotational symmetry at a temperature

Surface and electronic structure of SmB through scanning tunneling microscopy

T_{s}\approx 87

Evolution of the Kondo lattice and non-Fermi liquid excitations in a heavy-fermion metal

K. We investigated the electronic properties of FeSe using scanning tunneling microscopy/spectroscopy (STM/S), magnetization, and electrical transport measurements. The results indicated two new energy scales (i)

Surface and electronic structure of SmB6 through scanning tunneling microscopy

T^{*} \approx

Influence of disorder on the signature of the pseudogap and multigap superconducting behavior in FeSe

75 K denoted by an onset of electron-hole asymmetry in STS, enhanced spin fluctuations, and increased positive magnetoresistance; (ii)

Observation of Landau quantization and standing waves in HfSiS

T^{**} \approx