Quantum materials is an umbrella term in

condensed matter physics Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter, especially the solid and liquid State of matter, phases, that arise from electromagnetic forces between atoms and elec ...

that encompasses all materials whose essential properties cannot be described in terms of semiclassical particles and low-level

quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...

. These are materials that present strong electronic correlations or some type of electronic order, such as

superconducting Superconductivity is a set of physical properties observed in superconductors: materials where electrical resistance vanishes and magnetic fields are expelled from the material. Unlike an ordinary metallic conductor, whose resistance decreases g ...

or magnetic orders, or materials whose electronic properties are linked to ''non-generic'' quantum effects –

topological insulator A topological insulator is a material whose interior behaves as an electrical insulator while its surface behaves as an electrical conductor, meaning that electrons can only move along the surface of the material. A topological insulator is an ...

s, Dirac electron systems such as

graphene Graphene () is a carbon allotrope consisting of a Single-layer materials, single layer of atoms arranged in a hexagonal lattice, honeycomb planar nanostructure. The name "graphene" is derived from "graphite" and the suffix -ene, indicating ...

, as well as systems whose collective properties are governed by genuinely quantum behavior, such as ultra-cold atoms, cold

excitons An exciton is a bound state of an electron and an electron hole which are attracted to each other by the electrostatic Coulomb force resulting from their opposite charges. It is an electrically neutral quasiparticle regarded as an elementary ...

polaritons In physics, polaritons are bosonic quasiparticles resulting from strong coupling of electromagnetic waves (photon) with an electric or magnetic dipole-carrying excitation (state) of solid or liquid matter (such as a phonon, plasmon, or an exc ...

, and so forth. On the microscopic level, four fundamental degrees of freedom – that of charge, spin, orbit and lattice – become intertwined, resulting in complex electronic states; the concept of

emergence In philosophy, systems theory, science, and art, emergence occurs when a complex entity has properties or behaviors that its parts do not have on their own, and emerge only when they interact in a wider whole. Emergence plays a central rol ...

is a common thread in the study of quantum materials. Quantum materials exhibit puzzling properties with no counterpart in the macroscopic world: quantum entanglement, quantum fluctuations, robust boundary states dependent on the topology of the materials' bulk wave functions, etc. Quantum anomalies such as the

chiral magnetic effect Chiral magnetic effect (CME) is the generation of electric current along an external magnetic field induced by chirality imbalance. Fermions are said to be chiral if they keep a definite projection of spin quantum number on momentum. The CME is a ...

link some quantum materials with processes in high-energy physics of quark-gluon plasmas.

History

In 2012, Joseph Orenstein published an article in ''

Physics Today ''Physics Today'' is the membership magazine of the American Institute of Physics. First published in May 1948, it is issued on a monthly schedule, and is provided to the members of ten physics societies, including the American Physical Society. ...

'' about "ultrafast spectroscopy of quantum materials". Orenstein stated, As a paradigmatic example, Orenstein refers to the breakdown of Landau

Fermi liquid theory Fermi liquid theory (also known as Landau's Fermi-liquid theory) is a theoretical model of interacting fermions that describes the normal state of the conduction electrons in most metals at sufficiently low temperatures. The theory describes the ...

due to strong correlations. The use of the term "quantum materials" has been extended and applied to other systems, such as topological insulators, and Dirac electron materials. The term has gained momentum since the article "The rise of quantum materials" was published in ''

Nature Physics ''Nature Physics'' is a monthly peer-reviewed scientific journal published by Nature Portfolio. It was first published in October 2005 (volume 1, issue 1). The chief editor is David Abergel. Scope ''Nature Physics'' publishes both pure and appli ...

'' in 2016. Quoting:

References

{{Authority control Condensed matter physics Materials science Quantum mechanics