Engineering Anomalously Large Electron Transport in Topological Semimetals

Journal Article · 12 March 2024 · Advanced Materials

DOI: https://doi.org/10.1002/adma.202310944 · OSTI ID:2326118

Plisson, Vincent M.  ^[1]; Yao, Xiaohan ^[1]; Wang, Yaxian ^[2]; Varnavides, George ^[3]; Suslov, Alexey ^[4]; Graf, David ^[4]; Choi, Eun Sang ^[4]; Yang, Hung‐Yu ^[1]; Wang, Yiping ^[1]; Romanelli, Marisa ^[1]; McNamara, Grant ^[1]; Singh, Birender ^[1]; McCandless, Gregory T. ^[5]; Chan, Julia Y. ^[5]; Narang, Prineha ^[3]; Tafti, Fazel ^[1]; Burch, Kenneth S.  ^[1]

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1. Boston College, Chestnut Hill, MA (United States)
2. Chinese Academy of Sciences (CAS), Beijing (China)
3. Univ. of California, Los Angeles, CA (United States)
4. Florida State Univ., Tallahassee, FL (United States)
5. Baylor Univ., Waco, TX (United States)

Anomalous transport of topological semimetals has generated significant interest for applications in optoelectronics, nanoscale devices, and interconnects. Understanding the origin of novel transport is crucial to engineering the desired material properties, yet their orders of magnitude higher transport than single-particle mobilities remain unexplained. This work demonstrates the dramatic mobility enhancements result from phonons primarily returning momentum to electrons due to phonon-electron dominating over phonon–phonon scattering. Proving this idea, proposed by Peierls in 1932, requires tuning electron and phonon dispersions without changing symmetry, topology, or disorder. This is achieved by combining de Haas - van Alphen (dHvA), electron transport, Raman scattering, and first-principles calculations in the topological semimetals MX₂ (M = Nb, Ta and X = Ge, Si). Replacing Ge with Si brings the transport mobilities from an order magnitude larger than single particle ones to nearly balanced. This occurs without changing the crystal structure or topology and with small differences in disorder or Fermi surface. Simultaneously, Raman scattering and first-principles calculations establish phonon–electron dominated scattering only in the MGe₂ compounds. Thus, this study proves that phonon-drag is crucial to the transport properties of topological semimetals and provides insight to engineer these materials further.

• Research Organization: Boston College, Chestnut Hill, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE
• Grant/Contract Number: SC0023124; SC0018675
• OSTI ID: 2326118
• Alternate ID(s): OSTI ID: 2326119; OSTI ID: 2338171
• Journal Information: Advanced Materials, Vol. 36, Issue 24; ISSN 0935-9648
• Publisher: WileyCopyright Statement
• Country of Publication: United States
• Language: English