Related papers: Band gap opening at the Dirac point in Co/BiSbTeSe…
With angle-resolved photoemission spectroscopy, gap-opening is resolved at up to room temperature in the Dirac surface states of molecular beam epitaxy grown Cr-doped Bi2Se3 topological insulator films, which however show no long-range…
Point contact spectroscopy reveals a gap-like feature above the magnetic and structural transition temperatures for underdoped $Ba(Fe_{1-x}Co_x)_2As_2$, $SrFe_2As_2$ and $Fe_{1+y}Te$. The conductance spectrum starts showing an enhancement…
CO2 chemisorption on SrTiO3(001) surfaces is studied using ab initio calculations in order to establish new chemical sensing mechanisms. We find that CO2 adsorption opens the material band gap, however, while the adsorption on the…
We report X-ray diffraction patterns and calculated electronic band structures of the Dirac line-nodal material CaSb$_2$ under pressure. Its superconducting transition temperature ($T_{\mathrm{c}}=1.7$ K) increases under pressure and…
In this report, we identify the origin of the temperature dependence of the surface energy gap in impurity-doped topological insulators. The gap at the Dirac point and its variation with temperature were studied by using angle-resolved…
Opening a sizable band gap in the zero-gap germanene without heavy loss of carrier mobility is a key issue for its application in nanoelectronic devices such as high-performance field effect transistors (FETs) operating at room temperature.…
Magnetism breaks the time reversal symmetry expected to open a Dirac gap in 3D topological insulators that consequently leads to quantum anomalous Hall effect. The most common approach of inducing ferromagnetic state is by doping magnetic…
A Dirac-type energy spectrum was demonstrated in gapless ultra-short-period metamorphic InAsSb/InSb superlattices by angle-resolved photoemission spectroscopy (ARPES_ measurements. The Fermi velocity value 7.4x10^5 m/s in a gapless…
The substitution of bismuth by samarium in BiFeO3 is known to induce a structural phase transition from the polar phase to a non-polar phase, with a possible antiferroelectric intermediate structure. In this paper, we investigate the impact…
We report a room-temperature optical reflectivity study performed on [112]-oriented Cd$_3$As$_2$ single crystals over a broad energy range under external pressure up to 10 GPa. The abrupt drop of the band dispersion parameter…
Thermoelectric properties of two-dimensional (2D) Dirac materials are calculated within linearized Boltzmann transport theory and relaxation time approximation. We find that the gapless 2D Dirac material exhibits poorer thermoelectric…
In this report, we demonstrate that the energy gap in Cr-doped Bi2Se3 closes and reopens in oscillatory fashion with increasing sample thickness indicating the topological quantum phase transition driven by the quantum finite size effect.…
Since the advent of topological insulators hosting symmetry-protected Dirac surface states, efforts have been made to gap these states in a controllable way. A new route to accomplish this was opened up by the discovery of topological…
The band gap of periodically-doped graphene with hydrogen is investigated. It is found through a tight-binding model (TB) that for certain periodicities, called here NGPs (non-gap periodicities), no gap is opened at the Dirac point. This…
This study shows that the charge disproportionation at the Bi site in BaBiO$_3$ alters as a function of temperature. Decreasing the temperature from 300K down to 160K leads to a significant modification of the density of states…
Infrared reflectivity measurements of CeSb under multi-extreme conditions (low temperatures, high pressures and high magnetic fields) were performed. A pseudo gap structure, which originates from the magnetic band folding effect,…
The interaction between magnetic impurities and the gapless surface state is of critical importance for realizing novel quantum phenomena and new functionalities in topological insulators. By combining angle-resolved photoemission…
Al(110) has been studied for temperatures up to 900 K via ensemble density-functional molecular dynamics. The strong anharmonicity displayed by this surface results in a negative coefficient of thermal expansion, where the first interlayer…
The band bending (BB) effect on the surface of the second-generation topological insulators implies a serious challenge to design transport devices. The BB is triggered by the effective electric field generated by charged impurities close…
We have performed angle-resolved photoemission spectroscopy (ARPES) on CeBi which undergoes a two-step antiferromagnetic (AF) transition with temperature. Soft-x-ray ARPES has revealed the inverted band structure at the X point of bulk…