Quantum materials is an umbrella term in
condensed matter physics that encompasses all materials whose essential properties cannot be described in terms of
semiclassical particles and low-level
quantum mechanics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistr ...
.
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 certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike ...
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 an allotrope of carbon consisting of a single layer of atoms arranged in a hexagonal lattice nanostructure. , as well as systems whose collective properties are governed by genuinely quantum behavior, such as
Ultracold atom, 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. It is an electrically neutral quasiparticle that exists in insulators, semiconductors and some liquids. The ...
,
polaritons
In physics, polaritons are quasiparticles resulting from strong coupling of electromagnetic waves with an electric or magnetic dipole-carrying excitation. They are an expression of the common quantum phenomenon known as level repulsion, also ...
, 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 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 most metals at sufficiently low temperatures. The interactions among the particles of the many-body ...
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 Andrea Taroni, who is a full-time professional editor employed by this ...
'' in 2016.
Quoting:
References
{{Quantum-stub
Condensed matter physics
Materials science
Quantum mechanics