Electrical and optical properties of SnEuTe and SnSrTe films

Abstract

The SnTe, Sn 1−x Eu x Te and Sn 1−x Sr x Te ͑x Ͻ 0.06͒ films were prepared by hot wall epitaxy. The ternary alloy films prepared in cation rich condition had hole concentration around 1 ϫ 10 19 cm −3 with high mobility exceeding 2000 cm 2 / V s at room temperature. Optical transmission spectra were also measured in the temperature range from 100 to 400 K and compared with theoretical calculations. Optical transmission spectra of the SnTe were simulated successfully assuming bumped band edge structures. A band inversion model was proposed for the Sn 1−x Eu x Te and Sn 1−x Sr x Te systems, and the optical transmission spectra were also simulated successfully assuming the band inversion model.

Bonding diversity in rock salt-type tellurides: examining the interdependence between chemical bonding and materials properties

“…That is to say that the transition from a metallic to a semiconducting state appears as rather abrupt (like the metal-to-insulatortransitions induced by the formations of charge-densitywaves 85 ), while the changes in bonding nature look continuous and rather subtle within this series. Therefore, the series Y 1Àx Sn x Te, which has been studied to a lesser extent, 82,[86][87][88] appears to be an excellent candidate system to explore the inuence of chemical compositions 89,90 on the transition from a metallic to a semiconducting state. Clearly, the chemical composition inuences the chemical bonding but compositional changes translate into rather small and, in particular, continuous changes in chemical bonding; for the physical properties, the changes may turn out as drastic, as a function of the respective electronic band structure.…”

Topological band crossings in epitaxial strained SnTe

“…There are several works reporting the molecular-beam epitaxy (MBE) growth of SnTe (111) on different substrates such as BaF 2 (111) [18,19] and Bi 2 Te 3 [20,21]. The growth on Bi 2 Te 3 templates is particularly interesting due to nearly matching conditions.…”

Topological surface transport in epitaxial SnTe thin films grown on Bi2Te3

“…To obtain high-quality thin films by molecular beam epitaxy (MBE) [25][26][27][28][29][30][31][32], lattice matching of the substrate is crucial. In this regard, while BaF 2 is the usual choice of substrate for SnTe [33] with its ∼1.6% lattice matching, we noticed that rhombohedral Bi 2 Te 3 may be a better choice, at least for the (111) growth direction, with the lattice matching of ∼1.5%. Furthermore, the building block of Bi 2 Te 3 is a Te-Bi-Te-Bi-Te quintuple layer (QL) terminated with a hexagonal Te plane, which naturally accommodates the Sn layer of the SnTe in the (111) plane [see Fig.…”

“…3(b)] yields the Dingle temperature T D of 15 K, from which the mean-free path of Dirac electrons l SdH = 24 nm and their mobility μ SdH s = 2000 cm 2 /Vs are calculated [4]. Such a mobility is typical for best-quality SnTe films [33]. Now we discuss the origin of the observed n-type Dirac fermions.…”