This case is the result of strong e-e interactions which drastically quench the spinsinglet/spin-triplet energy gap, E ⊕ ST , within the same valley, making it smaller than the small energy gap, E V , between the two Si valleys, i.e., E V > E ⊕ ST . Related experimental situations have been reported in Refs. . The VFCI results concerning this case are presented in Sec. II A.