Pseudo-magnetic field-induced slow carrier dynamics in periodically strained graphene

The creation of pseudo-magnetic fields in strained graphene has emerged as a promising route to investigate intriguing physical phenomena that would be unattainable with labora- tory superconducting magnets. The giant pseudo-magnetic fields observed in highly deformed graphene can substantially alter the optical properties of graphene beyond a level that can be feasible with an external magnetic field, but the experimental signatures of the influence of such pseudo-magnetic fields have yet to be unveiled. Here, using time-resolved infrared pump-probe spectroscopy, we provide unambiguous evidence for slow carrier dynamics enabled by the pseudo-magnetic fields in periodically strained graphene. Strong pseudo-magnetic fields of ~100 T created by non-uniform strain in graphene on nanopillars are found to significantly decelerate the relaxation processes of hot carriers by more than an order of magnitude. Our findings offer alternative opportunities to harness the properties of graphene enabled by pseudo-magnetic fields for optoelectronics and condensed matter physics.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)Nanyang Technological UniversityNational Research Foundation (NRF)Published versionThe research of the project was in part supported by Ministry of Education, Singapore, under grant AcRF TIER 1 2019-T1-002-050 (RG 148/19 (S)). The research of the project was also supported by Ministry of Education, Singapore, under grant AcRF TIER 2 (MOE2018-T2-2-011 (S)). This work is also supported by National Research Foundation of Singapore through the Competitive Research Program (NRF-CRP19-2017-01). This work is also supported by National Research Foundation of Singapore through the NRFANR Joint Grant (NRF2018-NRF-ANR009 TIGER). This work is also supported by the iGrant of Singapore A*STAR AME IRG (A2083c0053). T.C.S. and D.G. acknowledge the financial support from Nanyang Technological University under the start-up grants M4080514 and M4081630. Q.J.W. acknowledges the financial support from Singapore Ministry of Education Academic Research Fund Tier 2 under grant no. MOE2018-T2-1- 176. The authors would like to acknowledge and thank the Nanyang NanoFabrication Centre (N2FC)