Pairing

Materials science

Physics

Superconductivity

Quantum mechanics

Electron

Cuprate

Condensed matter physics

Atomic orbital

Physical Review Letters

We study the electronic structure and superconductivity in CuO$_2$ monolayer grown recently on $d$-wave cuprate superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$. Density functional theory calculations indicate significant charge transfer across the interface such that the CuO$_2$ monolayer is heavily overdoped into the hole-rich regime yet inaccessible in bulk cuprates. We show that both the Cu $d_{x^2-y^2}$ and $d_{3z^2-r^2}$ orbitals become important and the Fermi surface contains one electron and one hole pocket associated with the two orbitals respectively. Constructing a minimal correlated two-orbital model for the $e_g$ complex, we show that the spin-orbital exchange interactions produce a nodeless superconductor with extended $s$-wave pairing symmetry and a pairing energy gap comparable to the bulk $d$-wave gap, in agreement with recent experiments. The findings point to a direction of realizing new high-$T_c$ superconductors in ozone grown transition-metal-oxide monolayer heterostructures.

Nodeless High- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>T</mml:mi><mml:mi>c</mml:mi></mml:msub></mml:math> Superconductivity in the Highly Overdoped <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>CuO</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math> Monolayer

Nodeless High- Tc Superconductivity in the Highly Overdoped CuO2 Monolayer