lessdoped

Lessdoped is an informal term used to describe a material that has a lower dopant concentration than a defined reference level. It is not a formal category in most scientific literatures, but it is commonly used to indicate samples with reduced carrier density relative to an optimally doped or fully doped state. The idea applies across systems where dopants introduce charge carriers, such as semiconductors and certain correlated electron materials.

In semiconductor physics, lower doping means fewer free carriers, higher resistivity, and a shift in electronic behavior toward intrinsic-like conduction at a given temperature. Heavily doped regimes can behave more metallic, while light doping can render a material more insulating or less conductive. Doping level thus directly controls the conductivity, carrier concentration, and Fermi level position.

In the field of high-temperature superconductivity, the standard terminology uses underdoped, optimally doped, and overdoped to describe samples with varying dopant levels relative to a maximum superconducting transition temperature. In this context, lessdoped can be viewed as synonymous with underdoped, indicating reduced hole or electron concentration and a phase diagram featuring suppressed Tc, the emergence of pseudogap behavior, and possible competing orders such as magnetism or charge order. For example, in cuprates like La2−xSrxCuO4 or YBa2Cu3O7−δ, decreasing dopant concentration or increasing oxygen deficiency moves the material into a lessdoped, underdoped regime with distinct electronic properties.

Measurement and control are achieved through synthesis and post-treatment methods that adjust dopant levels or oxygen content, such as chemical substitution, annealing, or controlled atmosphere processing. The term remains context-dependent and is sometimes preferred to be replaced by more precise qualifiers like underdoped or the exact dopant concentration.