Strongly Correlated Materials

Abstract

Strongly correlated materials are profoundly affected by the repulsive electron-electron interaction. This stands in contrast to many commonly used materials such as silicon and aluminum, whose properties are comparatively unaffected by the Coulomb repulsion. Correlated materials often have remarkable properties and transitions between distinct, competing phases with dramatically different electronic and magnetic orders. These rich phenomena are fascinating from the basic science perspective and offer possibilities for technological applications. This article looks at these materials through the lens of research performed at Rice University. Topics examined include: Quantum phase transitions and quantum criticality in "heavy fermion" materials and the iron pnictide high temperature superconductors; computational ab initio methods to examine strongly correlated materials and their interface with analytical theory techniques; layered dichalcogenides as example correlated materials with rich phases (charge density waves, superconductivity, hard ferromagnetism) that may be tuned by composition, pressure, and magnetic field; and nanostructure methods applied to the correlated oxides VO₂ and Fe₃O₄, where metal-insulator transitions can be manipulated by doping at the nanoscale or driving the system out of equilibrium. We conclude with a discussion of the exciting prospects for this class of materials.

Compositional phase stability of strongly correlated electron materials within DFT+ U

“…The formation energy increases monotonically with U and for U > 3 eV it becomes positive, corresponding to a prediction of phase separation. This indicates that the trend of a destabilization of compounds of intermediate x found previously in Li x FePO 4 23 also occurs for Li x CoO 2 . Furthermore, it demonstrates that such a trend is found even in the absence of CO.…”

“…3,4 Phenomenologically, SCMs exist in a ground state which is in the vicinity of a Mott transition 5,6 whereby electronic hopping may be overwhelmed by local interactions, resulting in an insulating state. Realizations of SCMs often contain atoms with open-shell d or f electrons, such as the high-temperature superconducting cuprates 7 , colossal magnetoresistance manganites 8 , and heavy fermion actinide based materials.…”

Ultrahigh‐Power Pseudocapacitors Based on Ordered Porous Heterostructures of Electron‐Correlated Oxides

“…Unlike transitions to superconductivity only taking place below the critical transition temperature, IMTs happen as temperature increases and thus enable these strongly correlated materials to behave metallic state in their high‐temperature phases,36, 37, 38, 39 which is expected to have practical applications. In this work, we report a classic strongly correlated TMO, vanadium sesquioxide (V 2 O 3 ), with a 3D bicontinuous nanoporous architecture (NP V 2 O 3 ) as a conductive network penetrating in all‐ceramic hybrid electrodes of V 2 O 3 /MnO 2 (NP V 2 O 3 /MnO 2 ) for high‐performance pseudocapacitors.…”

New materials for tunable plasmonic colloidal nanocrystals

“…One example is vanadium oxide (VO 2 ), which is an interesting material because it has a temperature dependent plasmonic resonance. 123 At room temperature, VO 2 is an insulator and therefore it cannot have plasmonic properties. Around 340 K, it has a conductor-insulator phase transition, above which LSPRs are clearly recognizable.…”

“…[123][124][125] They can feature a variety of phenomena, superconductivity and giant magneto-resistance being among the most known examples. 123 Among them, transition metal oxide NCs have been investigated in detail. In the context of plasmonics, it is worth remembering that many metal oxides are characterized by intrinsic conductive behaviour and can potentially be plasmonic.…”