Abstract
In a topological crystalline insulator (TCI) the inversion of the bulk valence and conduction bands is a necessary condition to observe surface metallic states. Solid solutions of Pb1-xSnxTe have been shown to be TCI, where band inversion occurs as a result of the band gap evolution upon alloying with Sn. The origins of this band inversion remain unclear. Herein the role of Sn insertion into the PbTe matrix is investigated for the p-type Pb1-xSnxTe series with x = 0, 0.35, 0.60, and 1.00 via nuclear magnetic resonance (NMR) and transport measurements. 207Pb, 119Sn, and 125Te line shapes, spin-lattice relaxation rates, and Knight shifts provide site-specific characterization of the electronic band structure. This probe of the electronic band structure shows that the band inversion is unaffected by lattice distortions but related to spatial electronic inhomogeneities formed by Sn incorporation into the PbTe matrix. Strong relativistic effects are found to be responsible for the band inversion, regardless of carrier type and concentration, suggesting a novel interpretation of the band gap evolution with composition. The temperature dependences of the NMR parameters reveal a negative temperature coefficient of the direct gap for SnTe and positive coefficient for PbTe.
| Original language | English |
|---|---|
| Article number | 1500117 |
| Journal | Advanced Electronic Materials |
| Volume | 1 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 2015 |
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Keywords
- band inversion
- electronic inhomogeneities
- lead tin telluride
- NMR properties
- topological crystalline insulator
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
Cite this
Site-Specific Contributions to the Band Inversion in a Topological Crystalline Insulator. / Koumoulis, Dimitrios; Chasapis, Thomas Christos; Leung, Belinda; Taylor, Robert E.; Stoumpos, Costas C.; Calta, Nicholas P.; Kanatzidis, Mercouri G; Bouchard, Louis Serge.
In: Advanced Electronic Materials, Vol. 1, No. 8, 1500117, 2015.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Site-Specific Contributions to the Band Inversion in a Topological Crystalline Insulator
AU - Koumoulis, Dimitrios
AU - Chasapis, Thomas Christos
AU - Leung, Belinda
AU - Taylor, Robert E.
AU - Stoumpos, Costas C.
AU - Calta, Nicholas P.
AU - Kanatzidis, Mercouri G
AU - Bouchard, Louis Serge
PY - 2015
Y1 - 2015
N2 - In a topological crystalline insulator (TCI) the inversion of the bulk valence and conduction bands is a necessary condition to observe surface metallic states. Solid solutions of Pb1-xSnxTe have been shown to be TCI, where band inversion occurs as a result of the band gap evolution upon alloying with Sn. The origins of this band inversion remain unclear. Herein the role of Sn insertion into the PbTe matrix is investigated for the p-type Pb1-xSnxTe series with x = 0, 0.35, 0.60, and 1.00 via nuclear magnetic resonance (NMR) and transport measurements. 207Pb, 119Sn, and 125Te line shapes, spin-lattice relaxation rates, and Knight shifts provide site-specific characterization of the electronic band structure. This probe of the electronic band structure shows that the band inversion is unaffected by lattice distortions but related to spatial electronic inhomogeneities formed by Sn incorporation into the PbTe matrix. Strong relativistic effects are found to be responsible for the band inversion, regardless of carrier type and concentration, suggesting a novel interpretation of the band gap evolution with composition. The temperature dependences of the NMR parameters reveal a negative temperature coefficient of the direct gap for SnTe and positive coefficient for PbTe.
AB - In a topological crystalline insulator (TCI) the inversion of the bulk valence and conduction bands is a necessary condition to observe surface metallic states. Solid solutions of Pb1-xSnxTe have been shown to be TCI, where band inversion occurs as a result of the band gap evolution upon alloying with Sn. The origins of this band inversion remain unclear. Herein the role of Sn insertion into the PbTe matrix is investigated for the p-type Pb1-xSnxTe series with x = 0, 0.35, 0.60, and 1.00 via nuclear magnetic resonance (NMR) and transport measurements. 207Pb, 119Sn, and 125Te line shapes, spin-lattice relaxation rates, and Knight shifts provide site-specific characterization of the electronic band structure. This probe of the electronic band structure shows that the band inversion is unaffected by lattice distortions but related to spatial electronic inhomogeneities formed by Sn incorporation into the PbTe matrix. Strong relativistic effects are found to be responsible for the band inversion, regardless of carrier type and concentration, suggesting a novel interpretation of the band gap evolution with composition. The temperature dependences of the NMR parameters reveal a negative temperature coefficient of the direct gap for SnTe and positive coefficient for PbTe.
KW - band inversion
KW - electronic inhomogeneities
KW - lead tin telluride
KW - NMR properties
KW - topological crystalline insulator
UR - http://www.scopus.com/inward/record.url?scp=84977097939&partnerID=8YFLogxK
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U2 - 10.1002/aelm.201500117
DO - 10.1002/aelm.201500117
M3 - Article
VL - 1
JO - Advanced Electronic Materials
JF - Advanced Electronic Materials
SN - 2199-160X
IS - 8
M1 - 1500117
ER -