Table 1 Properties for the WZ-type MnSe0.5Te0.5 alloys compared to the RS-type MnSe and NC-type MnTe parent compounds.

Listed are the calculated direct (d) or indirect (i) electronic band gaps (Egel), the hole and electron effective masses (me* and mh*), the calculated and measured piezoelectric coefficient (d33), and experimentally determined values for the optical band gaps (Egopt). The results of experimental measurements of piezoelectric response and electrical resistivity are provided in figs. S2 and S3.

Materialsd33
(pm/V)
d33
(pm/V)
me*/m0mh*/m0Egel
(eV)
Egopt
(eV)
PolymorphTheoryExperimentTheoryTheoryTheoryExperiment
RS-MnSe0.781.572.52 (i)2.50
WZ-MnSe0.5Te0.59.541.5–110.301.802.71 (d)2.70
NC-MnTe1.261.540.98 (i)1.45