Related papers: Electrostatic modification of infrared response in…
We report infrared studies of the insulator-to-metal transition (IMT) in GaAs doped with either magnetic (Mn) or non-magnetic acceptors (Be). We observe a resonance with a natural assignment to impurity states in the insulating regime of…
The Metal-Insulator transition (MIT) in VO2 is characterized by the complex interplay among lattice, electronic and orbital degrees of freedom. In this contribution we investigated the strain-modulation of the orbital hierarchy and the…
Ordinary doping by electrons (holes) generally means that the Fermi level shifts towards the conduction band (valence band) and that the conductivity of free carriers increases. Recently, however, some peculiar doping characteristics were…
VO2, of interest for decades due to both its phenomenology and its potential applications, has a monoclinic distortion of the rutile crystal structure at ambient temperature that is coupled to its metal-insulator transition (MIT). In…
We present infrared ab-plane conductivity data for the layered cobaltate Na$_x$CoO$_2$ at three different doping levels ($x=0.25, 0.50$, and 0.75). The Drude weight increases monotonically with hole doping, $1-x$. At the lowest hole doping…
Modulation-doped AlGaAs/GaAs heterostructures are utilized extensively in the study of quantum transport in nanostructures, but charge fluctuations associated with remote ionized dopants often produce deleterious effects. Electric…
High temperature superconductivity in cuprates is realized by doping the Mott insulator with charge carriers. A central issue is how such an insulating state can evolve into a conducting or superconducting state when charge carriers are…
Optical anisotropy in crystalline solids enables direction-dependent light-matter interactions and underpins a variety of advanced photonic functionalities. In this context, Vanadium dioxide (VO2) represents a prototypical material that…
We investigated nonlinear conduction in bulk single crystals of VO2 with precise temperature control. Two distinct nonequilibrium phenomena were identified: a gradual reduction of the charge gap and a current-induced insulator-metal…
The Insulator-Metal-Transition adjoined by a structural transition of VO2 is induced above room temperature (340 K) by heating or self-heating. A steep resistance-jump of up to five orders of magnitude occurs at this transition in high…
Transition metal dichalcogenides exhibit rich phase diagrams dominated by the interplay of superconductivity and charge density waves, which often result in anomalies in the electric transport properties. Here, we employ the ionic gating…
The optical properties of vanadium dioxide ($VO_2$) can be tuned via metal-insulator transition. In this work different types of one-dimensional photonic structure-based microcavities that embed vanadium dioxide have been studied in the…
Neodymium nickelate, NdNiO3 attracts attraction due to the simultaneous occurrence of several phase transitions around the same temperature. The electronic properties of NdNiO3 are extremely complex as structural distortion, electron…
Electrostatic carrier doping using a field-effect-transistor structure is an intriguing approach to explore electronic phases by critical control of carrier concentration. We demonstrate the reversible control of the insulator-metal…
Long regarded as a model system for studying insulator-to-metal phase transitions, the correlated electron material vanadium dioxide (VO$_2$) is now finding novel uses in device applications. Two of its most appealing aspects are its…
One of the major puzzles in condensed matter physics has been the observation of a Mott-insulating state away from half-filling. The filling-controlled Mott insulator-metal transition, induced via charge-carrier doping, has been extensively…
First principles calculations through density functional theory (DFT)+$U$ method were performed to assess the effect of Li interstitial doping on the optoelectronic properties of NiO and of cubic, hexagonal, and monoclinic WO$_3$. The…
Using a combination of {\it ab initio} bandstructure methods and dynamical mean-field theory we study the single-particle spectrum of the prototypical charge-transfer insulator NiO. Good agreement with photoemission and…
We use scanning tunneling microscopy to visualize the atomic-scale electronic states induced by a pair of hole dopants in Ca2CuO2Cl2 parent Mott insulator of cuprates. We find that when the two dopants approach each other, the transfer of…
It is widely recognised that the effect of doping into a Mott insulator is complicated and unpredictable, as can be seen by examining the Hall coefficient in high $T_{\rm c}$ cuprates. The doping effect, including the electron-hole doping…