Existence of electron and hole pockets and partial gap opening in the correlated semimetal Ca 3 Ru 2 O 7

Hui Xing, Libin Wen, Chenyi Shen, Jiaming He, Xinxin Cai, Jin Peng, Shun Wang, Mingliang Tian, Zhu An Xu, Wei Ku, Zhiqiang Mao, Ying Liu

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The electronic band structure of correlated Ca3Ru2O7 featuring an antiferromagnetic (AFM) as well as a structural transition has been determined theoretically at high temperatures, which has led to the understanding of the remarkable properties of Ca3Ru2O7, such as the bulk spin-valve effects. However, its band structure and Fermi surface (FS) below the structural transition have not been resolved, even though a FS consisting of electron pockets was found experimentally. Here we report magnetoelectrical transport and thermoelectric measurements with the electric current and temperature gradient directed along the a and b axes, respectively, of an untwined single crystal of Ca3Ru2O7. The thermopowers obtained along the two crystal axes were found to show opposite signs at low temperatures, demonstrating the presence of both electron and hole pockets on the FS. In addition, how the FS evolves across T∗=30K at which a distinct transition from coherent to incoherent behavior occurs was also inferred: the Hall and Nernst coefficient results suggest a temperature- and momentum-dependent partial gap opening in Ca3Ru2O7 below the structural transition with a possible Lifshitz transition occurring at T∗. The experimental demonstration of a correlated semimetal ground state in Ca3Ru2O7 calls for further theoretical studies of this remarkable material.

Original languageEnglish (US)
Article number041113
JournalPhysical Review B
Volume97
Issue number4
DOIs
StatePublished - Jan 19 2018

Bibliographical note

Funding Information:
The authors have benefited from discussions with A. Leggett, Y. Chen, H. Sun, and D. Qian. The work performed at SJTU was supported by MOST (Grant No. 2015CB921104), NSFC (Grants No. 91421304 and No. 11474198), the Fundamental Research Funds for the Central Universities, at Pennsylvania State University by the NSF (Grant No. EFMA1433378), at ZJU was supported by the NSFC under Grants No. U1332209 and No. 11774305, at CAS by the NSFC Grant No. U1432251, and the CAS/SAFEA international partnership program for creative research teams of China, at Tulane supported by the U.S. Department of Energy under EPSCoR Grant No. DE-SC0012432 with additional support from the Louisiana Board of Regents.

Funding Information:
The authors have benefited from discussions with A. Leggett, Y. Chen, H. Sun, and D. Qian. The work performed at SJTU was supported by MOST (Grant No. 2015CB921104), NSFC (Grants No. 91421304 and No. 11474198), the Fundamental Research Funds for the Central Universities, at Pennsylvania State University by the NSF (Grant No. EFMA1433378), at ZJU was supported by the NSFC under Grants No. U1332209 and No. 11774305, at CAS by the NSFC Grant No. U1432251, and the CAS/SAFEA international partnership program for creative research teams of China, at Tulane supported by the U.S. Department of Energy under EPSCoR Grant No. DE-SC0012432 with additional support from the Louisiana Board of Regents.

Publisher Copyright:
© 2018 American Physical Society.

Fingerprint

Dive into the research topics of 'Existence of electron and hole pockets and partial gap opening in the correlated semimetal Ca 3 Ru 2 O 7'. Together they form a unique fingerprint.

Cite this