1
|
Rodrigues JNB, Wagner LK. Identifying materials with charge-spin physics using charge-spin susceptibility computed from first principles. J Chem Phys 2020; 153:074105. [PMID: 32828081 DOI: 10.1063/1.5144911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors present a quantity termed charge-spin susceptibility, which measures the charge response to spin degrees of freedom in strongly correlated materials. This quantity is simple to evaluate using both standard density functional theory and many-body electronic structure techniques, enabling comparison between different levels of theory. A benchmark on 28 layered magnetic materials shows that large values of charge-spin susceptibility correlate with unconventional ground states such as disordered magnets and unconventional superconductivity.
Collapse
Affiliation(s)
- J N B Rodrigues
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Lucas K Wagner
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| |
Collapse
|
2
|
Tang HK, Leaw JN, Rodrigues JNB, Herbut IF, Sengupta P, Assaad FF, Adam S. Response to Comment on "The role of electron-electron interactions in two-dimensional Dirac fermions". Science 2019; 366:366/6470/eaav8877. [PMID: 31806787 DOI: 10.1126/science.aav8877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 11/04/2019] [Indexed: 11/02/2022]
Abstract
Hesselmann et al question one of our conclusions: the suppression of Fermi velocity at the Gross-Neveu critical point for the specific case of vanishing long-range interactions and at zero energy. The possibility they raise could occur in any finite-size extrapolation of numerical data. Although we cannot definitively rule out this possibility, we provide mathematical bounds on its likelihood.
Collapse
Affiliation(s)
- Ho-Kin Tang
- Centre for Advanced 2D Materials, National University of Singapore, 117546 Singapore.,Department of Physics, Faculty of Science, National University of Singapore, 117542 Singapore
| | - J N Leaw
- Centre for Advanced 2D Materials, National University of Singapore, 117546 Singapore.,Department of Physics, Faculty of Science, National University of Singapore, 117542 Singapore
| | - J N B Rodrigues
- Centre for Advanced 2D Materials, National University of Singapore, 117546 Singapore.,Department of Physics, Faculty of Science, National University of Singapore, 117542 Singapore
| | - I F Herbut
- Department of Physics, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - P Sengupta
- Centre for Advanced 2D Materials, National University of Singapore, 117546 Singapore.,School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - F F Assaad
- Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - S Adam
- Centre for Advanced 2D Materials, National University of Singapore, 117546 Singapore. .,Department of Physics, Faculty of Science, National University of Singapore, 117542 Singapore.,Yale-NUS College, 138527 Singapore
| |
Collapse
|
3
|
Liu Y, Rodrigues JNB, Luo YZ, Li L, Carvalho A, Yang M, Laksono E, Lu J, Bao Y, Xu H, Tan SJR, Qiu Z, Sow CH, Feng YP, Neto AHC, Adam S, Lu J, Loh KP. Tailoring sample-wide pseudo-magnetic fields on a graphene-black phosphorus heterostructure. Nat Nanotechnol 2018; 13:828-834. [PMID: 29941889 DOI: 10.1038/s41565-018-0178-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 05/23/2018] [Indexed: 05/22/2023]
Abstract
Spatially tailored pseudo-magnetic fields (PMFs) can give rise to pseudo-Landau levels and the valley Hall effect in graphene. At an experimental level, it is highly challenging to create the specific strain texture that can generate PMFs over large areas. Here, we report that superposing graphene on multilayer black phosphorus creates shear-strained superlattices that generate a PMF over an entire graphene-black phosphorus heterostructure with edge size of tens of micrometres. The PMF is intertwined with the spatial period of the moiré pattern, and its spatial distribution and intensity can be modified by changing the relative orientation of the two materials. We show that the emerging pseudo-Landau levels influence the transport properties of graphene-black phosphorus field-effect transistor devices with Hall bar geometry. The application of an external magnetic field allows us to enhance or reduce the effective field depending on the valley polarization with the prospect of developing a valley filter.
Collapse
Affiliation(s)
- Yanpeng Liu
- Department of Chemistry, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
| | - J N B Rodrigues
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Yong Zheng Luo
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Linjun Li
- Department of Chemistry, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
| | - Alexandra Carvalho
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Ming Yang
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore
| | - Evan Laksono
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Junpeng Lu
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Yang Bao
- Department of Chemistry, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
| | - Hai Xu
- Department of Chemistry, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
| | - Sherman J R Tan
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Zhizhan Qiu
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Chorng Haur Sow
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Yuan Ping Feng
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - A H Castro Neto
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Shaffique Adam
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore.
- Department of Physics, National University of Singapore, Singapore, Singapore.
- Yale-NUS College, Singapore, Singapore.
| | - Jiong Lu
- Department of Chemistry, National University of Singapore, Singapore, Singapore.
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore.
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, Singapore, Singapore.
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore.
| |
Collapse
|
4
|
Tang HK, Leaw JN, Rodrigues JNB, Herbut IF, Sengupta P, Assaad FF, Adam S. The role of electron-electron interactions in two-dimensional Dirac fermions. Science 2018; 361:570-574. [DOI: 10.1126/science.aao2934] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 05/25/2018] [Indexed: 11/02/2022]
|
5
|
Tang HK, Laksono E, Rodrigues JNB, Sengupta P, Assaad FF, Adam S. Interaction-Driven Metal-Insulator Transition in Strained Graphene. Phys Rev Lett 2015; 115:186602. [PMID: 26565484 DOI: 10.1103/physrevlett.115.186602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Indexed: 06/05/2023]
Abstract
The question of whether electron-electron interactions can drive a metal to insulator transition in graphene under realistic experimental conditions is addressed. Using three representative methods to calculate the effective long-range Coulomb interaction between π electrons in graphene and solving for the ground state using quantum Monte Carlo methods, we argue that, without strain, graphene remains metallic and changing the substrate from SiO_{2} to suspended samples hardly makes any difference. In contrast, applying a rather large-but experimentally realistic-uniform and isotropic strain of about 15% seems to be a promising route to making graphene an antiferromagnetic Mott insulator.
Collapse
Affiliation(s)
- Ho-Kin Tang
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - E Laksono
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - J N B Rodrigues
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
| | - P Sengupta
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - F F Assaad
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - S Adam
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore
- Yale-NUS College, 16 College Avenue West, Singapore 138527, Singapore
| |
Collapse
|
6
|
Lin AL, Rodrigues JNB, Su C, Milletari M, Loh KP, Wu T, Chen W, Neto AHC, Adam S, Wee ATS. Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite. Sci Rep 2015; 5:11430. [PMID: 26100970 PMCID: PMC4477240 DOI: 10.1038/srep11430] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 05/05/2015] [Indexed: 11/26/2022] Open
Abstract
Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation is manipulated for functionality. Here we demonstrate an iron-oxide and graphene oxide nanocomposite based device that acts as a tunable ferromagnet at room temperature. Not only can we tune its transition temperature in a wide range of temperatures around room temperature, but the magnetization can also be tuned from zero to 0.011 A m2/kg through an initialization process with two readily accessible knobs (magnetic field and electric current), after which the system retains its magnetic properties semi-permanently until the next initialization process. We construct a theoretical model to illustrate that this tunability originates from an indirect exchange interaction mediated by spin-imbalanced electrons inside the nanocomposite.
Collapse
Affiliation(s)
- Aigu L Lin
- 1] NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore,28 Medical Drive, Singapore 117456 [2] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [3] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542
| | - J N B Rodrigues
- 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542
| | - Chenliang Su
- 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - M Milletari
- 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542
| | - Kian Ping Loh
- 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Tom Wu
- Materials Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Wei Chen
- 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - A H Castro Neto
- 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542
| | - Shaffique Adam
- 1] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [2] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542 [3] Yale-NUS College, 16 College Ave West, Singapore 138527
| | - Andrew T S Wee
- 1] NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore,28 Medical Drive, Singapore 117456 [2] Centre for Advanced 2D Materials and Graphene Research Centre, Faculty of Science, National University of Singapore, 6 Science Drive 2, Singapore 117546 [3] Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117542
| |
Collapse
|
7
|
Abstract
We develop an analytical scattering formalism for computing the transmittance through periodic defect lines within the tight-binding model of graphene. We first illustrate the method with a relatively simple case, the pentagon-only defect line. Afterwards, more complex defect lines are treated, namely the zz(558) and the zz(5757) ones. The formalism developed uses only simple tight-binding concepts, reducing the problem to matrix manipulations which can be easily worked out by any computational algebraic calculator.
Collapse
Affiliation(s)
- J N B Rodrigues
- CFP and Departamento de Física e Astronomia, Faculdade de Ciências Universidade do Porto, P-4169-007 Porto, Portugal
| | | | | |
Collapse
|
8
|
Peres NMR, Rodrigues JNB, Stauber T, Lopes Dos Santos JMB. Dirac electrons in graphene-based quantum wires and quantum dots. J Phys Condens Matter 2009; 21:344202. [PMID: 21715777 DOI: 10.1088/0953-8984/21/34/344202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In this paper we analyse the electronic properties of Dirac electrons in finite-size ribbons and in circular and hexagonal quantum dots. We show that due to the formation of sub-bands in the ribbons it is possible to spatially localize some of the electronic modes using a p-n-p junction. We also show that scattering of confined Dirac electrons in a narrow channel by an infinitely massive wall induces mode mixing, giving a qualitative reason for the fact that an analytical solution to the spectrum of Dirac electrons confined in a square box has not yet been found. A first attempt to solve this problem is presented. We find that only the trivial case k = 0 has a solution that does not require the existence of evanescent modes. We also study the spectrum of quantum dots of graphene in a perpendicular magnetic field. This problem is studied in the Dirac approximation, and its solution requires a numerical method whose details are given. The formation of Landau levels in the dot is discussed. The inclusion of the Coulomb interaction among the electrons is considered at the self-consistent Hartree level, taking into account the interaction with an image charge density necessary to keep the back-gate electrode at zero potential. The effect of a radial confining potential is discussed. The density of states of circular and hexagonal quantum dots, described by the full tight-binding model, is studied using the Lanczos algorithm. This is necessary to access the detailed shape of the density of states close to the Dirac point when one studies large systems. Our study reveals that zero-energy edge states are also present in graphene quantum dots. Our results are relevant for experimental research in graphene nanostructures. The style of writing is pedagogical, in the hope that newcomers to the subject will find this paper a good starting point for their research.
Collapse
Affiliation(s)
- N M R Peres
- Centro de Física e Departamento de Física, Universidade do Minho, P-4710-057, Braga, Portugal
| | | | | | | |
Collapse
|