title: High-pressure superconducting phase diagram of 6Li: isotope effects in dense lithium.
abstract: We measured the superconducting transition temperature of (6)Li between 16 and 26 GPa, and report the lightest system to exhibit superconductivity to date. The superconducting phase diagram of (6)Li is compared with that of (7)Li through simultaneous measurement in a diamond anvil cell (DAC). Below 21 GPa, Li exhibits a direct (the superconducting coefficient, α, T(c) proportional M(-α), is positive), but unusually large isotope effect, whereas between 21 and 26 GPa, lithium shows an inverse superconducting isotope effect. The unusual dependence of the superconducting phase diagram of lithium on its atomic mass opens up the question of whether the lattice quantum dynamic effects dominate the low-temperature properties of dense lithium.
authors.affiliation: Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Schaeffer
authors.affiliation: Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Temple
authors.affiliation: Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112.
authors.forename: Jasmine K
authors.initials: JK
authors.lastname: Bishop
authors.affiliation: Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 deemyad@physics.utah.edu.
authors.forename: Shanti
authors.initials: S
authors.lastname: Deemyad
keywords: isotope; lithium; pressure; quantum effects; superconductivity