[1]
V. Keppens, D. Mandrus, B.C. Sales, B.C. Chakoumakos, P. Dai, R. Coldea, M.B. Maple, D.A. Gajewski, E.J. Freeman, S. BenningtonLocalized vibrational modes in metallic solidsNature, 395 (1998), pp. 876-878
[2]
W. Schweika, R.P. Hermann, M. Prager, J. Per?on, V. KeppensDumbbell rattling in thermoelectric zinc antimonyPhys Rev Lett, 99 (2007), p. 125501
[3]
P. Wei, W. Zhao, D. Tang, W. Zhu, X. Nie, Q. ZhangOn the relevance between fine structure and enhanced performance of skutterudite thermoelectric materials: X-ray spectroscopy studiesJ Materiomics, 2 (2016), pp. 280-289
[4]
A. Bentien, M. Christensen, J.D. Bryan, A. Sanchez, S. Paschen, F. Steglich, G.D. Stucky, B.B. IversenThermal conductivity of thermoelectric clathratesPhys Rev B, 69 (2004), Article 045107
[5]
A. Prokofiev, A. Sidorenko, K. Hradil, M. Ikeda, R. Svagera, M. Waas, H. Winkler, K. Neumaier, S. PaschenThermopower enhancement by encapsulating cerium in clathrate cagesNat Mater, 12 (2013), pp. 1096-1101
[6]
J. Cohn, G.S. Nolas, V. Fessatidis, T.H. Metcalf, G.A. SlackGlasslike heat conduction in high-mobility crystalline semiconductorsPhys Rev Lett, 82 (1999), p. 779
[7]
J. Fulmer, O.I. Lebedev, V.V. Roddatis, D.C. Kaseman, S. Sen, J.A. Dolyniuk, K. Lee, A.V. Olenev, K. KovnirClathrate Ba8Au16P30: the “gold standard” for lattice thermal conductivityJ Am Chem Soc, 135 (2013), p. 12313
[8]
J. Dong, O.F. Sankey, C.W. MylesTheoretical study of the lattice thermal conductivity in Ge framework semiconductorsPhys Rev Lett, 86 (2001), p. 2361
[9]
T. Kume, H. Fukuoka, T. Koda, S. Sasaki, H. Shimizu, S. YamanakaHigh-pressure Raman study of Ba doped silicon clathratePhys Rev Lett, 90 (2003), p. 155503
[10]
M. Christensen, N. Lock, J. Overgaard, B.B. IversenCrystal structures of thermoelectric n-and p-type Ba8Ga16Ge30 studied by single crystal, multitemperature, neutron diffraction, conventional X-ray diffraction and resonant synchrotron X-ray diffractionJ Am Chem Soc, 128 (2006), p. 15657
[11]
I. Zerec, V. Keppens, M.A. McGuire, D. Mandrus, B.C. Sales, P. ThalmeierFour-well tunneling states and elastic response of clathratesPhys Rev Lett, 92 (2004), p. 185502
[12]
Y. He, G. GalliNanostructured clathrate phonon glasses: beyond the rattling conceptNano Lett, 14 (2014), p. 2920
[13]
M. Christensen, A.B. Abrahamsen, N.B. Christensen, F. Juranyi, N.H. Andersen, K. Lefmann, J. Andreasson, C.R. Bahl, B.B. IversenAvoided crossing of rattler modes in thermoelectric materialsNat Mater, 7 (2008), pp. 811-815
[14]
Y. Takasu, T. Hasegawa, N. Ogita, M. Udagawa, M.A. Avila, K. Suekuni, T. TakabatakeOff-center rattling and anisotropic expansion of type-I clathrates studied by Raman scatteringPhys Rev Lett, 100 (2008), p. 165503
[15]
T. Mori, K. Iwamoto, S. Kushibiki, H. Honda, H. Matsumoto, N. Toyota, M.A. Avila, K. Suekuni, T. TakabatakeOptical conductivity spectral anomalies in the off-center rattling system β-Ba8Ga16Sn30Phys Rev Lett, 106 (2011), Article 015501
[16]
L. Gil, M.A. Ramos, A. Bringer, U. BuchenauLow-temperature specific heat and thermal conductivity of glassesPhys Rev Lett, 70 (1993), p. 182
[17]
B.C. Sales, B.C. Chakoumakos, R. Jin, J.R. Thompson, D. MandrusStructural, magnetic, thermal, and transport properties of X8Ga16Ge30 (X = Eu, Sr, Ba) single crystalsPhys Rev B, 63 (2001), p. 245113
[18]
R.P. Hermann, V. Keppens, P. Bonville, G.S. Nolas, F. Grandjean, G.J. Long, H.M. Christen, B.C. Chakoumakos, B.C. Sales, D. MandrusDirect experimental evidence for atomic tunneling of europium in crystalline Eu8Ga16Ge30Phys Rev Lett, 97 (2006), Article 017401
[19]
L. Qiu, I.P. Swainson, G.S. Nolas, M.A. WhiteStructure, thermal, and transport properties of the clathrates Sr8Zn8Ge38, Sr8Ga16Ge30, and Ba8Ga16Si30Phys Rev B, 70 (2004), Article 035208
[20]
J. Tang, T. Rachi, R. Kumashiro, M.A. Avila, K. Suekuni, T. Takabatake, F. Guo, K. Kobayashi, K. Akai, K. TanigakiEnergetics of endohedral atoms in type-I clathrates observed by soft X-ray spectroscopyPhys Rev B, 78 (2008), Article 085203
[21]
J. Xu, J. Tang, K. Sato, Y. Tanabe, H. Miyasaka, M. Yamashita, S. Heguri, K. TanigakiLow-temperature heat capacity of Sr8Ga16Ge30 and Ba8Ga16Ge30: tunneling states and electron-phonon interaction in clathratesPhys Rev B, 82 (2010), Article 085206
[22]
R. Baumbach, F. Bridges, L. Downward, D. Cao, P. Chesler, B. SalesOff-center phonon scattering sites in Eu8Ga16Ge30 and Sr8Ga16Ge30Phys Rev B, 71 (2005), Article 024202
[23]
A. Fujiwara, K. Sugimoto, C.-H. Shih, H. Tanaka, J. Tang, Y. Tanabe, J. Xu, S. Heguri, K. Tanigaki, M. TakataQuantitative relation between structure and thermal conductivity in type-I clathrates X8Ga16Ge30 (X = Sr, Ba) based on electrostatic-potential analysisPhys Rev B, 85 (2012), p. 144305
[24]
J. Wu, K. Akagi, J. Xu, H. Shimotani, K.K. Huynh, K. TanigakiUnification of the low-energy excitation peaks in the heat capacity that appears in clathratesPhys Rev B, 93 (2016), Article 094303
[25]
K. Suekuni, Y. Takasu, T. Hasegawa, N. Ogita, M. Udagawa, M.A. Avila, T. TakabatakeOff-center rattling modes and glasslike thermal conductivity in the type-I clathrate Ba8Ga16Sn30Phys Rev B, 81 (2010), p. 205207
[26]
M.A. Avila, K. Suekuni, K. Umeo, H. Fukuoka, S. Yamanaka, T. TakabatakeGlasslike versus crystalline thermal conductivity in Carrier-tuned Ba8Ga16X30 clathrates (X = Ge, Sn)Phys Rev B, 74 (2006), p. 125109
[27]
Y. Takasu, T. Hasegawa, N. Ogita, M. Udagawa, M.A. Avila, K. Suekuni, T. TakabatakeOff-center rattling and cage vibration of the Carrier-tuned type-I clathrate Ba8Ga16Ge30 studied by Raman scatteringPhys Rev B, 82 (2010), p. 134302
[28]
T. Mori, S. Goshima, K. Iwamoto, S. Kushibiki, H. Matsumoto, N. Toyota, K. Suekuni, M.A. Avila, T. Takabatake, T. Hasegawa, N. Ogita, M. UdagawaOptical conductivity of rattling phonons in type-I clathrate Ba8Ga16Ge30Phys Rev B, 79 (2009), p. 212301
[29]
F. Bridges, L. DownwardPossible mechanism for glass-like thermal conductivities in crystals with off-center atomsPhys Rev B, 70 (2004), p. 140201
[30]
K. Suekuni, M.A. Avila, K. Umeo, H. Fukuoka, S. Yamanaka, T. Nakagawa, T. TakabatakeSimultaneous structure and Carrier tuning of dimorphic clathrate Ba8Ga16Sn30Phys Rev B, 77 (2008), p. 235119
[31]
J. Tang, Z. Li, T. Nishiro, K. Sato, K. TanigakiCarrier tuning of type-I clathrate single crystalsJ Phys Chem Solid, 71 (2010), pp. 480-482
[32]
J. Tang, R. Kumashiro, J. Ju, Z. Li, M.A. Avila, K. Suekuni, T. Takabatake, F. Guo, K. Kobayashi, K. TanigakiP- and n-Type Ba8Ga16Ge30 studied by X-ray photoelectron spectroscopyChem Phys Lett, 472 (2009), pp. 60-64
[33]
S.J. Pennycook, L.A. BoatnerChemically sensitive structure-imaging with a scanning transmission electron microscopeNature, 336 (1988), pp. 565-567
[34]
S.D. Findlay, N. Shibata, H. Sawada, E. Okunishi, Y. Kondo, T. Yamamoto, Y. IkuharaRobust atomic resolution imaging of light elements using scanning transmission electron microscopyAppl Phys Lett, 95 (2009), p. 191913
[35]
T. Takabatake, K. Suekuni, T. Nakayama, E. KaneshitaPhonon-glass electron-crystal thermoelectric clathrates: experiments and theoryRev Mod Phys, 86 (2014), p. 669
[36]
J. CallawayModel for lattice thermal conductivity at low temperaturesPhys Rev, 113 (1959), p. 1046