相关论文: False metals, real insulators, and degenerate gapp…

In materials science, point defects play a crucial role in materials properties. This is particularly well known for the wide band gap insulators where the defect formation/compensation determines the equilibrium Fermi level and generally…

We present a microscopic picture rationalizing the surprisingly steep decrease of the band gap with temperature in insulators, crystalline or otherwise. The gap narrowing largely results from fluctuations of long-wavelength optical…

Traditional solid-state physics has long correlated the optical properties of materials with their electronic structures. However, recent discoveries of intrinsic gapped metals have challenged this classical view. Gapped metals possess…

Gapped metals, a recently proposed class of materials, possess a band gap slightly above or below the Fermi level, behaving as intrinsic p- or n-type semiconductors without requiring external doping. Inspired by this concept, we propose a…

A key to understand how electrons behave in crystalline solids is the band structure that connects the energy of electron waves to their wavenumber (k). Even in the phase of matter with only short-range order (liquid or amorphous solid),…

The theory of the 2k_F and 4k_F instabilities in quarter-filled band organic conductors is revisited. The phase angles of the 2k_F bond and charge density waves are shown to change as electron correlation is turned on, and this switching of…

The layered iron superconductors are discussed using electronic structure calculations. The four families of compounds discovered so far, including Fe(Se,Te) have closely related electronic structures. The Fermi surface consists of…

Although most insulators are expected to undergo insulator to metal transition on lattice compression, tetrahedral semiconductors Si, GaAs and InSb can become metallic on compression as well as by expansion. We focus on the transition by…

In modern condensed matter theory, phases of electronic matter--such as metals and insulators-are fundamentally distinguished by the presence or absence of charge-carrying quasiparticles or excitations near the Fermi surface at low…

Topological insulators have emerged as a major topic of condensed matter physics research with several novel applications proposed. Although there are now a number of established experimental examples of materials in this class, all of them…

The correlation-driven metal-insulator transition (MIT) of BaVS$_3$ was studied by polarized infrared spectroscopy. In the metallic state two types of electrons coexist at the Fermi energy: The quasi 1D metallic transport of $A_{1g}$…

Strongly correlated quantum matter exhibits a rich variety of remarkable properties, but the organizing principles that underlie the behavior remain to be established. Graphene heterostructures, which can host narrow moire electron bands…

The transition between gapped (semiconducting) and gapless (metallic) phases and tunability of bandgap in materials is a very lucrative yet considerably challenging goal for new-age device preparation. For bulk materials and for…

I present an informal discussion of various cases where two-dimensional surface metal-insulator structural and charge-density-wave instabilities driven by partly filled surface states have been advocated. These include reconstructions of…

A granular metal is an array of metallic nano-particles imbedded into an insulating matrix. Tuning the intergranular coupling strength a granular system can be transformed into either a good metal or an insulator and, in case of…

Material scientists and condensed matter physicists have long been divided on the issue of choosing the conceptual framework for explaining why open-shell transition-metal oxides tend to be insulators, whereas otherwise successful theories…

We report measurements and calculations on the properties of the intermetallic compound Be$_5$Pt. High-quality polycrystalline samples show a nearly constant temperature dependence of the electrical resistivity over a wide temperature…

Self-consistent theory of electron localization in disordered systems is generalized for the case of interacting electrons. We propose and critically compare a number of possible self-consistency schemes which take into account the lowest…

We calculate the corrections to the conductivity and compressibility of a disordered metal when the mean free path is smaller than the screening length. Such a condition is shown to be realized for low densities and large disorder. Analysis…

It has been found that periodically closely spaced vacancies on a graphite sheet cause a significant rearrange-ment of its electronic spectrum: metallic waveguides with a high density of states near the Fermi level are formed along the…