中国物理B ›› 2022, Vol. 31 ›› Issue (10): 106501-106501.doi: 10.1088/1674-1056/ac8928

• • 上一篇    下一篇

Unusual thermodynamics of low-energy phonons in the Dirac semimetal Cd3As2

Zhen Wang(王振)1,2, Hengcan Zhao(赵恒灿)1, Meng Lyu(吕孟)1, Junsen Xiang(项俊森)1, Qingxin Dong(董庆新)1,2, Genfu Chen(陈根富)1,2,3, Shuai Zhang(张帅)1,2,3, and Peijie Sun(孙培杰)1,2,3,†   

  1. 1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2. School of Physical Science, University of Chinese Academy of Sciences, Beijing 100049, China;
    3. Songshan Lake Materials Laboratory, Dongguan 523808, China
  • 收稿日期:2022-05-11 修回日期:2022-06-10 出版日期:2022-10-16 发布日期:2022-09-24
  • 通讯作者: Peijie Sun E-mail:pjsun@iphy.ac.cn
  • 基金资助:
    This work was supported by the National Natural Science Foundation of China (Grant Nos. 11974389, 12141002 and 52088101), the National Key R&D Program of China (Grant No. 2017YFA0303100), the Chinese Academy of Sciences through the Scientific Instrument Developing Project (Grant No. ZDKYYQ20210003), and the Strategic Priority Research Program (Grant No. XDB33000000).

Unusual thermodynamics of low-energy phonons in the Dirac semimetal Cd3As2

Zhen Wang(王振)1,2, Hengcan Zhao(赵恒灿)1, Meng Lyu(吕孟)1, Junsen Xiang(项俊森)1, Qingxin Dong(董庆新)1,2, Genfu Chen(陈根富)1,2,3, Shuai Zhang(张帅)1,2,3, and Peijie Sun(孙培杰)1,2,3,†   

  1. 1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2. School of Physical Science, University of Chinese Academy of Sciences, Beijing 100049, China;
    3. Songshan Lake Materials Laboratory, Dongguan 523808, China
  • Received:2022-05-11 Revised:2022-06-10 Online:2022-10-16 Published:2022-09-24
  • Contact: Peijie Sun E-mail:pjsun@iphy.ac.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (Grant Nos. 11974389, 12141002 and 52088101), the National Key R&D Program of China (Grant No. 2017YFA0303100), the Chinese Academy of Sciences through the Scientific Instrument Developing Project (Grant No. ZDKYYQ20210003), and the Strategic Priority Research Program (Grant No. XDB33000000).

摘要: By studying the thermal conductivity, specific heat, elastic modulus, and thermal expansion as a function of temperature for Cd3As2, we have unveiled a couple of important thermodynamic features of the low-energy phonons strongly interacting with Dirac electrons. The existence of soft optical phonons, as inferred from the extremely low thermal conductivity, is unambiguously confirmed by low-temperature specific heat revealing significant deviation from Debye's description. The estimated Debye temperature is small in the range of 100—200 K and varies significantly depending upon the measurement used in its experimental determination. The thermodynamic Grüneisen ratio γ reveals a remarkable reduction below about 100 K, an energy scale that is highly relevant to the Dirac states, towards negative values below about 10 K that are indicative of lattice instability.

关键词: Dirac semimetal, low-energy phonon, thermal conductivity, lattice instability

Abstract: By studying the thermal conductivity, specific heat, elastic modulus, and thermal expansion as a function of temperature for Cd3As2, we have unveiled a couple of important thermodynamic features of the low-energy phonons strongly interacting with Dirac electrons. The existence of soft optical phonons, as inferred from the extremely low thermal conductivity, is unambiguously confirmed by low-temperature specific heat revealing significant deviation from Debye's description. The estimated Debye temperature is small in the range of 100—200 K and varies significantly depending upon the measurement used in its experimental determination. The thermodynamic Grüneisen ratio γ reveals a remarkable reduction below about 100 K, an energy scale that is highly relevant to the Dirac states, towards negative values below about 10 K that are indicative of lattice instability.

Key words: Dirac semimetal, low-energy phonon, thermal conductivity, lattice instability

中图分类号:  (Thermal properties of crystalline solids)

  • 65.40.-b
65.40.De (Thermal expansion; thermomechanical effects) 63.20.kd (Phonon-electron interactions)