Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors wish to acknowledge Prof. Terry Tritt (Clemson University) for providing access to low temperature measurement facilities in his laboratory, and Prof. Julian Goldsmid, Dr. Pooja Puneet, and Prakash Parajuli for valuable discussions. We also thank National Institute of Standards and Technology and Dr. Jeffrey W. Lynn for providing the neutron beam time that made the neutron rocking curve measurements possible. R.P.H. thanks Dipanshu Bansal and Jiawang Hong for numerical phonon data in refs (11) and (26).