The Effect of Janus Asymmetry on Thermal Transport in SnSSe

Abstract

Several ternary “Janus” metal dichalcogenides such as {Mo,Zr,Pt}-SSe have emerged as candidates with significant potential for optoelectronic, piezoelectric, and thermoelectric applications. SnSSe, a natural option to explore as a thermoelectric given that its “parent” structures are SnS 2 and SnSe 2 has, however, only recently been shown to be mechanically stable. Here, we calculate the lattice thermal conductivities of the Janus SnSSe monolayer along with those of its parent dicalchogenides. The phonon frequencies of SnSSe are intermediate between those of SnSe 2 and SnS 2 ; however, its thermal conductivity is the lowest of the three and even lower than that of a random Sn[S 0.5 Se 0.5 ] 2 alloy. This can be attributed to the breakdown of inversion symmetry and manifests as a subtle effect beyond the reach of the relaxation-time approximation. Together with its low favorable power factor, its thermal conductivity confirms SnSSe as a good candidate for thermoelectric applications.

Enhanced vertical polarization and ultra-low polarization switching barriers of two-dimensional SnS/SnSSe ferroelectric heterostructures

“…Optimized lattice parameters for SnS with β phase and SnSSe monolayers are 3.734 Å and 3.763 Å, respectively, which greatly agree with previous results. 39–42 These two similar lattice parameters lead to a small lattice mismatch (only 0.8%). Here, six different stacking configurations for SnS/SnSSe are considered (Fig.…”

“…These results are almost similar to previous studies. [39][40][41][42] Projected band structures (Fig. 3(c)) demonstrate that the ground state of SnS/SnSSe exhibits a narrower indirect bandgap E g of 0.824 eV (HSE06) and 0.377 eV (PBE, Table 1).…”

A bifunctional GeC/SnSSe heterostructure for highly efficient photocatalysts and photovoltaic devices

“…29 Recent studies demonstrated that the Janus SnSSe monolayer has a strain-tunable electronic structure, high mobility of holes, and exceptionally high absorption in the visible light region. [29][30][31][32][33][34][35] As such it is an interesting material for photocatalysts. As is known, Janus MoSSe and WSSe monolayers have been successfully fabricated using the CVD method.…”

The structural, mechanical, electronic, and optical properties of Janus Hf2CXY (X, Y = O, S, Se or Te, X ≠ Y) MXenes

“…Tunable valley polarization in MoSSe monolayer can be achieved by magnetic doping and strain engineering [11]. Recently, similar to the Janus TMD dichalcogenide monolayer, many other Janus materials have been studied, such as Janus TMD halogenides [12,13], Janus group-III chalcogenides [14][15][16][17], Janus group-IV chalcogenides [18,19], and Janus MXenes [20][21][22].…”