Supplementary Information for “Thermoelectric performance

of co-doped SnTe with resonant levels”

Min Zhou,1 Zachary M. Gibbs,2 Heng Wang,3 Yemao Han,1 Laifeng Li,1,1) and G. Jeffrey Snyder,3,4,a)

1Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese

Academy of Sciences, Beijing 100190, China.

2Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E.

California Blvd. Pasadena, CA 91125, USA.

3Materials Science, California Institute of Technology, 1200 California Blvd., Pasadena, CA

91125, USA.

4TMO University, Saint Petersburg Russia.

1a) Authors to whom correspondence should be addressed. Electronic addresses: laifengli@mail.ipc.ac.cn and jsnyder@caltech.edu

Figure S1. Thermoelectric properties of co-doped In0.0025Sn0.9975Te1-yIy and In0.0025AgzSn0.9975-zTe alloys. (a) resistivity, (b) Seebeck coefficient, (c) thermal conductivity, (d) zT values. The black

open square data are from Zhang’s report1.

Figure S2. Thermoelectric properties of co-doped In0.005Sn0.995Te1-yIy and In0.005AgzSn0.995-zTe alloys. (a) resistivity, (b) Seebeck coefficient, (c) thermal conductivity, (d) zT values. The black open

square data are from Zhang’s report1.

Figure S3. (a) X-ray diffraction patterns of co-doped In0.01Sn0.99Te0.99Iy and In0.01AgzSn0.99-zTe alloys. (1) In0.01Sn0.99Te alloy, (2) In0.01Sn0.99Te0.995I0.005, (3) In0.01Sn0.99Te0.99I0.01, (4)

In0.01Sn0.99Te0.985I0.015, (5) In0.01Ag0.005Sn0.985Te, (6) In0.01Ag0.01Sn0.98Te, (7) In0.01Ag0.015Sn0.975Te.(b) Lattice constants of co-doped In0.01Sn0.99Te0.99Iy and In0.01AgzSn0.99-zTe alloys as function

of I/Ag content, being consistent with Vegard’s law. For some In/I-codoped SnTe samples, small diffraction peaks of Te phase were observed. On the other hand, diffraction peaks of Sn phase were observed in In0.01Ag0.005Sn0.985Te sample. The impurity phases in the above samples could be related to the complex effects of co-doping on the solubility of In, I and Ag in co-doped In0.01Sn0.99Te0.99Iy

and In0.01AgzSn0.99-zTe alloys.

Figure S4 Temperature dependence of the percentage of the Seebeck coefficient enhancement (/), where, / refers to (In0.01Sn0.99Te-SnTe1.005)/SnTe1.005. The In-doped In0.01Sn0.99Te and the

un-doped SnTe1.005 without resonant levels have the same carrier density (nH21020 cm-3) at room temperature. The enhancement of the Seebeck coefficient decreases as temperature increases

over a wide temperature range (350-773 K).

Figure S5. The electronic thermal conductivity of the co-doped In0.01Sn0.99Te1-yIy and In0.01AgzSn0.99-

zTe alloys.

Table S1 The stabilization region width of the co-doped InxSn1-xTe1-yIy and InxAgzSn1-x-zTe compounds with different Indium content (x=0.0025, 0.005, 0.01). In the stabilization region each Indium atom was supposed to supply 2 electrons (In1+ to In3+). This width should be adjusted

depending on the particular dopant efficiency.Indium content (x) The number density of

Indium (NIn) (cm-3)The stabilization region

width (cm-3)0.0025 3.941019 7.871019

0.005 7.871019 1.571020

0.01 1.571020 3.151020

Table S2 The measured Hall carrier concentration (nH) of In0.01Sn0.99Te1-yIy and In0.01AgzSn0.99-zTe compounds at room temperature

Composition nH (cm-3)In0.01Sn0.99Te 2.221020

In0.01Sn0.99Te0.995I0.005 1.921020

In0.01Sn0.99Te0.99I0.01 1.711020

In0.01Sn0.99Te0.985I0.015 1.841020

In0.01Ag0.005Sn0.985Te 1.111020

In0.01Ag0.01Sn0.98Te 3.801020

In0.01Ag0.015Sn0.975Te 4.791020

References:1. Q. Zhang, B. Liao, Y. Lan, K. Lukas, W. Liu, K. Esfarjani, C. Opeil, D. Broido, G. Chen and Z. Ren,

Proceedings of the National Academy of Sciences of the United States of America, 2013, 110, 13261-13266.