Electronic structure and transport properties of SrAl2Si2: Effect of yttrium substitution

► We report the effects of yttrium substitution for the Sr1−xYxAl2Si2 alloys. ► Upon Y substitution, the electrical resistivity of SrAl2Si2 decreases notably. ► Yttrium substitution may introduce dislocations or/and twins to SrAl2Si2. ► Theoretical studies reveal that a shift in the EF occurs upon Y substitution.