Superconducting states by doping magnetic Mott insulators on the anisotropic triangular lattice

Abstract We investigate the superconducting state of t − J model on an anisotropic triangular lattice with smoothly tunable frustration using variational Monte Carlo simulations. At half filling, we identify three distinct magnetic Mott insulating states, Néel antiferromagnetic state, spiral magnetic state and one dimensional antiferromagnetic state with the increase of next-nearest-neighbor spin interaction J 2 . Upon doping these magnetic Mott insulating states, distinct superconducting states are realized. The pairing symmetry of superconducting state evolves with the next-nearest-neighbor hopping t 2 and the associated interaction J 2 , which controls the frustration of the system. A time-reversal-symmetry breaking s + d + id -wave superconducting pairing is identified near the isotropic limit t 2 / t 1 ≈ 1, connecting the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>d</mml:mi> </mml:mrow> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>x</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mo>−</mml:mo> <mml:msup> <mml:mrow> <mml:mi>y</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:msub> </mml:math> -wave at smaller t 2 / t 1 and s + d xy -wave at larger t 2 / t 1 . The effective Fermi surface is renormalized, resembling that of a square lattice for t 2 / t 1 ≲ 0.9 and a one-dimensional lattice along the diagonal bond for t 2 / t 1 ≳ 1.2, highlighting the impact of strong correlations on pairing symmetry. The superconducting states are commonly featured by short range spin correlations, suggesting the intricate interplay between superconducting state and the spin background.