Mott Transition in VO2 Revealed by Infrared Spectroscopy and Nano-Imaging

  title={Mott Transition in VO2 Revealed by Infrared Spectroscopy and Nano-Imaging},
  author={M. M. Qazilbash and Markus Brehm and Byung Gyu Chae and Pei-Chun Ho and Gregory O. Andreev and Bong Jun Kim and Sun Jin Yun and Alexander V. Balatsky and M B Maple and Fritz Keilmann and Hyun-Tak Kim and Dimitri Basov},
  pages={1750 - 1753}
Electrons in correlated insulators are prevented from conducting by Coulomb repulsion between them. When an insulator-to-metal transition is induced in a correlated insulator by doping or heating, the resulting conducting state can be radically different from that characterized by free electrons in conventional metals. We report on the electronic properties of a prototypical correlated insulator vanadium dioxide in which the metallic state can be induced by increasing temperature. Scanning near… 

Imaging the nanoscale phase separation in vanadium dioxide thin films at terahertz frequencies

Multi-modal THz and mid-IR nano-imaging is used to examine the phase transition in VO2 thin films, and the unexpectedly smooth transition at THz frequencies is discussed in the context of a dimer Hubbard model.

Infrared spectroscopy and nano-imaging of the insulator-to-metal transition in vanadium dioxide

We present a detailed infrared study of the insulator-to-metal transition IMT in vanadium dioxide VO2 thin films. Conventional infrared spectroscopy was employed to investigate the IMT in the far

Metal-insulator transition in vanadium dioxide nanobeams: probing sub-domain properties of strongly correlated materials

Many strongly correlated electronic materials, including high-temperature superconductors, colossal magnetoresistance and metal-insulator-transition (MIT) materials, are inhomogeneous on a

Internal strain tunes electronic correlations on the nanoscale

This work uses cryogenic scanning near-field optical microscopy to study the metal-to-insulator transition in an electronically driven charge-ordered system with a 20-nm spatial resolution, and observes pronounced phase segregation with a sharp boundary between metallic and insulating regions evidencing its first-order nature.

Inhomogeneity of the ultrafast insulator-to-metal transition dynamics of VO2

The results suggest an electronic mechanism dominating the photoinduced IMT, but also highlight the difficulty to deduce microscopic mechanisms when the true intrinsic material response is yet unclear.

New aspects of the metal-insulator transition in single-domain vanadium dioxide nanobeams.

New aspects of the metal-insulator transition are reported, studied in single-domain vanadium dioxide nanobeams, with observed supercooling of the metallic phase by 50 degrees C, an activation energy in the insulating phase that is consistent with the optical gap, and a connection between theMetal- insulator transition and the equilibrium carrier density in theinsulating phase.

Quantum Sensing of Insulator‐to‐Metal Transitions in a Mott Insulator

Nitrogen vacancy (NV) centers, optically active atomic defects in diamond, have attracted tremendous interest for quantum sensing, network, and computing applications due to their excellent quantum

Terahertz-field-induced insulator-to-metal transition in vanadium dioxide metamaterial

The observation of an insulator–metal transition in vanadium dioxide induced by a terahertz electric field is reported, demonstrating that integration of metamaterials with complex matter is a viable pathway to realize functional nonlinear electromagnetic composites.

Low-temperature dielectric anomaly arising from electronic phase separation at the Mott insulator-metal transition

Coulomb repulsion among conduction electrons in solids hinders their motion and leads to a rise in resistivity. A regime of electronic phase separation is expected at the first-order phase transition

Nanoscale Control of Oxygen Defects and Metal-Insulator Transition in Epitaxial Vanadium Dioxides.

It is found that applying electric voltages of different polarity through an SPM tip locally changes the contact potential difference and conductivity on the surface of VO2 by modulating the oxygen stoichiometry.



Mechanism and observation of Mott transition in VO2-based two- and three-terminal devices

When holes of about 0.018% are induced into a conduction band (breakdown of critical on-site Coulomb energy), an abrupt first-order Mott metal–insulator transition (MIT) rather than a continuous

Dynamical singlets and correlation-assisted Peierls transition in VO2.

It is found that VO2 is not a conventional Mott insulator, but that the formation of dynamical V-V singlet pairs due to strong Coulomb correlations is necessary to trigger the opening of a Peierls gap.

Monoclinic and correlated metal phase in VO(2) as evidence of the Mott transition: coherent phonon analysis.

In femtosecond pump-probe measurements, the appearance of coherent phonon oscillations at 4.5 and 6.0 THz indicating the rutile metal phase of VO2 does not occur simultaneously with the first-order

Correlated metallic state of vanadium dioxide

The metal-insulator transition and unconventional metallic transport in vanadium dioxide (VO$_2$) are investigated with a combination of spectroscopic ellipsometry and reflectance measurements. The

Surface versus bulk characterizations of electronic inhomogeneity in a VO2 thin film

thin film, theMIT should occur during the percolation process. We also used surface-sensitive scanning tunneling spectros-copy STS to investigate the microscopic evolution of the MIT near the surface.

Metal-insulator transitions

Metal-insulator transitions are accompanied by huge resistivity changes, even over tens of orders of magnitude, and are widely observed in condensed-matter systems. This article presents the

Electrodynamics of high- T c superconductors

Recent studies of the electromagnetic response of high-Tc superconductors using terahertz, infrared, and optical spectroscopies are reviewed. In combination these experimental techniques provide a

Sum rules and electrodynamics of high-T c cuprates in the pseudogap state

We explore connections between the electronic density of states ~DOS! in a conducting system and the frequency dependence of the scattering rate 1/t(v) inferred from infrared spectroscopy. We show

Direct Observation of Percolation in a Manganite Thin Film

The ferromagnetic domains almost disappear at a temperature T P2 higher than T P1, showing a local magnetic hysteresis in agreement with the resistivity hysteResis, indicating magnetic inhomogeneity.

Evidence of a pressure-induced metallization process in monoclinic VO2.

Differently from P=0, where the VO2 metallic phase is found only in conjunction with the rutile structure above 340 K, a new RT metallic phase within a monoclinic structure appears accessible in the high pressure regime.