Fig. 2: Structural signatures of R-SRO and E-SRO in Si0.125Ge0.625Sn0.25.
From: Coexistence of two types of short-range order in Si–Ge–Sn medium-entropy alloys
a The averaged local tetrahedral structural motif around each alloying element when the alloy adopts a random distribution, R-SRO and E-SRO. b, c Show the SRO polygons constructed from the averaged SRO parameter \({\alpha }_{ij}^{1}\) for each type of nearest neighbor in R-SRO and E-SRO, respectively. The averaged SRO parameter \({\alpha }_{ij}^{1}\) for the pair i − j is depicted as a dot on the axis labeled as i − j, with its location determined by the value of \({\alpha }_{ij}^{1}\). An SRO polygon (purple solid lines) is obtained through connecting the six dots. The dashed-hexagon represents a random distribution where \({\alpha }_{ij}^{1}=0\). It is visibly clear that only Ge–Sn and Sn–Sn in R-SRO display substantial deviations from the random distribution, whereas the six types of pairs in E-SRO all show strong non-random distributions.
