TY - JOUR
T1 - Quantum-critical conductivity of the Dirac fluid in graphene
AU - Gallagher, Patrick
AU - Yang, Chan Shan
AU - Lyu, Tairu
AU - Tian, Fanglin
AU - Kou, Rai
AU - Zhang, Hai
AU - Watanabe, Kenji
AU - Taniguchi, Takashi
AU - Wang, Feng
N1 - Funding Information:
Terahertz measurements were primarily supported by the Office of Naval Research under award N00014-15-1-2651. Sample fabrication was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under contract DE-AC02-05-CH11231 (van der Waals heterostructures program, KCWF16). P.G. was supported by the Heising-Simons Junior Fellowship program of the Kavli ENSI at Berkeley. C.-S.Y. was supported by the Ministry of Science and Technology under grant 105-2917-I-564-026. R.K. was supported by the JSPS Overseas Research Fellowship program. Growth of hexagonal boron nitride crystals (K.W., T.T.) was supported by the Elemental Strategy Initiative conducted by the MEXT, Japan, and the CREST (JPMJCR15F3), JST.
Publisher Copyright:
© 2017 The Authors.
PY - 2019
Y1 - 2019
N2 - Graphene near charge neutrality is expected to behave like a quantum-critical, relativistic plasma-the "Dirac fluid"-in which massless electrons and holes collide at a rapid rate. We used on-chip terahertz spectroscopy to measure the frequency-dependent optical conductivity of clean, micrometer-scale graphene at electron temperatures between 77 and 300 kelvin. At charge neutrality, we observed the quantum-critical scattering rate characteristic of the Dirac fluid. At higher doping, we detected two distinct current-carrying modes with zero and nonzero total momenta, a manifestation of relativistic hydrodynamics. Our work reveals the quantum criticality and unusual dynamic excitations near charge neutrality in graphene.
AB - Graphene near charge neutrality is expected to behave like a quantum-critical, relativistic plasma-the "Dirac fluid"-in which massless electrons and holes collide at a rapid rate. We used on-chip terahertz spectroscopy to measure the frequency-dependent optical conductivity of clean, micrometer-scale graphene at electron temperatures between 77 and 300 kelvin. At charge neutrality, we observed the quantum-critical scattering rate characteristic of the Dirac fluid. At higher doping, we detected two distinct current-carrying modes with zero and nonzero total momenta, a manifestation of relativistic hydrodynamics. Our work reveals the quantum criticality and unusual dynamic excitations near charge neutrality in graphene.
UR - http://www.scopus.com/inward/record.url?scp=85062987405&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85062987405&partnerID=8YFLogxK
U2 - 10.1126/science.aat8687
DO - 10.1126/science.aat8687
M3 - Article
C2 - 30819930
AN - SCOPUS:85062987405
SN - 0036-8075
VL - 364
SP - 158
EP - 162
JO - Science
JF - Science
IS - 6436
ER -