  We extend the relativistic Hartree-Fock (RHF) theory to study the structure
of single-$\Lambda$ hypernuclei. The density dependence is taken in both
meson-nucleon and meson-hyperon coupling strengths, and the induced
$\Lambda$-nucleon ($\Lambda N$) effective interactions are determined by
fitting $\Lambda$ separation energies to the experimental data for several
single-$\Lambda$ hypernuclei. The equilibrium of nuclear dynamics described by
the RHF model in normal atomic nuclei, namely, the balance between nuclear
attractive and repulsive interactions, is then found to be drastically changed
in single-$\Lambda$ hypernuclei, revealing a different role of Fock terms via
$\Lambda$ hyperon from the nucleon exchange. Since only one hyperon exists in a
single-$\Lambda$ hypernucleus, the overwhelmed $\Lambda N$ and $\Lambda\Lambda$
attractions via the Hartree than the $\Lambda\Lambda$ repulsion from the Fock
terms require an alternation of meson-hyperon coupling strengths in RHF to
rebalance the effective nuclear force with the strangeness degree of freedom,
leading to an improved description of $\Lambda$ Dirac mass and correspondingly
a systematically reduced $\sigma$-$\Lambda$ coupling strength
$g_{\sigma\Lambda}$ in current models as compared to those relativistic
mean-field (RMF) approaches without Fock terms. As a result, the effective
$\Lambda$ spin-orbit coupling potential in the ground state of hypernuclei is
suppressed, and these RHF models predict correspondingly a quenching effect in
$\Lambda$ spin-orbit splitting in comparison with the RMF cases. Furthermore,
the $\Lambda$ spin-orbit splitting could decrease efficiently by evolving the
hyperon-relevant couplings $g_{\sigma\Lambda}$ and $g_{\omega\Lambda}$
simultaneously, where to reconcile with the empirical value the RHF models
address a larger parameter space of meson-hyperon couplings.
