Dynamical susceptibility near a long-wavelength critical point with a nonconserved order parameter
We study the dynamic response of a two-dimensional system of itinerant fermions in the vicinity of a uniform (Q=0) Ising nematic quantum critical point of d-wave symmetry. The nematic order parameter is not a conserved quantity, and this permits a nonzero value of the fermionic polarization in the d...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2018
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| Online Access: | http://hdl.handle.net/1721.1/114684 |
| _version_ | 1826207107746103296 |
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| author | Klein, Avraham Lederer, Samuel Chowdhury, Debanjan Berg, Erez Chubukov, Andrey |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Klein, Avraham Lederer, Samuel Chowdhury, Debanjan Berg, Erez Chubukov, Andrey |
| author_sort | Klein, Avraham |
| collection | MIT |
| description | We study the dynamic response of a two-dimensional system of itinerant fermions in the vicinity of a uniform (Q=0) Ising nematic quantum critical point of d-wave symmetry. The nematic order parameter is not a conserved quantity, and this permits a nonzero value of the fermionic polarization in the d-wave channel even for vanishing momentum and finite frequency: Π(q=0,Ω[subscript m])≠0. For weak coupling between the fermions and the nematic order parameter (i.e., the coupling is small compared to the Fermi energy), we perturbatively compute Π(q=0,Ω[subscript m])≠0 over a parametrically broad range of frequencies where the fermionic self-energy Σ(ω) is irrelevant, and use Eliashberg theory to compute Π(q=0,Ω[subscript m]) in the non-Fermi-liquid regime at smaller frequencies, where Σ(ω)>ω. We find that Π(q=0,Ω) is a constant, plus a frequency-dependent correction that goes as |Ω| at high frequencies, crossing over to |Ω|[superscript 1/3] at lower frequencies. The |Ω|[superscript 1/3] scaling holds also in a non-Fermi-liquid regime. The nonvanishing of Π(q=0,Ω) gives rise to additional structure in the imaginary part of the nematic susceptibility χ″(q,Ω) at Ω>v[subscript F]q, in marked contrast to the behavior of the susceptibility for a conserved order parameter. This additional structure may be detected in Raman scattering experiments in the d-wave geometry. |
| first_indexed | 2024-09-23T13:44:14Z |
| format | Article |
| id | mit-1721.1/114684 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T13:44:14Z |
| publishDate | 2018 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/1146842022-09-28T15:49:59Z Dynamical susceptibility near a long-wavelength critical point with a nonconserved order parameter Klein, Avraham Lederer, Samuel Chowdhury, Debanjan Berg, Erez Chubukov, Andrey Massachusetts Institute of Technology. Department of Physics Lederer, Samuel Chowdhury, Debanjan We study the dynamic response of a two-dimensional system of itinerant fermions in the vicinity of a uniform (Q=0) Ising nematic quantum critical point of d-wave symmetry. The nematic order parameter is not a conserved quantity, and this permits a nonzero value of the fermionic polarization in the d-wave channel even for vanishing momentum and finite frequency: Π(q=0,Ω[subscript m])≠0. For weak coupling between the fermions and the nematic order parameter (i.e., the coupling is small compared to the Fermi energy), we perturbatively compute Π(q=0,Ω[subscript m])≠0 over a parametrically broad range of frequencies where the fermionic self-energy Σ(ω) is irrelevant, and use Eliashberg theory to compute Π(q=0,Ω[subscript m]) in the non-Fermi-liquid regime at smaller frequencies, where Σ(ω)>ω. We find that Π(q=0,Ω) is a constant, plus a frequency-dependent correction that goes as |Ω| at high frequencies, crossing over to |Ω|[superscript 1/3] at lower frequencies. The |Ω|[superscript 1/3] scaling holds also in a non-Fermi-liquid regime. The nonvanishing of Π(q=0,Ω) gives rise to additional structure in the imaginary part of the nematic susceptibility χ″(q,Ω) at Ω>v[subscript F]q, in marked contrast to the behavior of the susceptibility for a conserved order parameter. This additional structure may be detected in Raman scattering experiments in the d-wave geometry. Gordon and Betty Moore Foundation (Grant GBMF-4303) 2018-04-12T19:34:36Z 2018-04-12T19:34:36Z 2018-04 2018-03 2018-04-10T18:00:31Z Article http://purl.org/eprint/type/JournalArticle 2469-9950 2469-9969 http://hdl.handle.net/1721.1/114684 Klein, Avraham et al. "Dynamical susceptibility near a long-wavelength critical point with a nonconserved order parameter." Physical Review B 97, 15 (April 2018): 155115 © 2018 American Physical Society en http://dx.doi.org/10.1103/PhysRevB.97.155115 Physical Review B Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. American Physical Society application/pdf American Physical Society American Physical Society |
| spellingShingle | Klein, Avraham Lederer, Samuel Chowdhury, Debanjan Berg, Erez Chubukov, Andrey Dynamical susceptibility near a long-wavelength critical point with a nonconserved order parameter |
| title | Dynamical susceptibility near a long-wavelength critical point with a nonconserved order parameter |
| title_full | Dynamical susceptibility near a long-wavelength critical point with a nonconserved order parameter |
| title_fullStr | Dynamical susceptibility near a long-wavelength critical point with a nonconserved order parameter |
| title_full_unstemmed | Dynamical susceptibility near a long-wavelength critical point with a nonconserved order parameter |
| title_short | Dynamical susceptibility near a long-wavelength critical point with a nonconserved order parameter |
| title_sort | dynamical susceptibility near a long wavelength critical point with a nonconserved order parameter |
| url | http://hdl.handle.net/1721.1/114684 |
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