Taking the clue from the modern theory of polarization [Rev. Mod. Phys. 66, 899 (1994)RMPHAT0034-686110.1103/RevModPhys.66.899], we identify an operator to distinguish between Z2-even (trivial) and Z2-odd (topological) insulators in two spatial dimensions. Its definition extends the position operator [Phys. Rev. Lett. 82, 370 (1999)PRLTAO0031-900710.1103/PhysRevLett.82.370], which was introduced in one-dimensional systems. We first show a few examples of noninteracting models where single-particle wave functions are defined and allow for a direct comparison with standard techniques on large system sizes. Then, we illustrate its applicability for an interacting model on a small cluster where exact diagonalizations are available. Its formulation in the Fock space allows a direct computation of expectation values over the ground-state wave function (or any approximation of it), thus, allowing us to investigate generic interacting systems, such as strongly correlated topological insulators.
Real-space many-body marker for correlated Z2 topological insulators / Gilardoni, I.; Becca, F.; Marrazzo, A.; Parola, A.. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - 106:16(2022), pp. 1-5. [10.1103/PhysRevB.106.L161106]
Real-space many-body marker for correlated Z2 topological insulators
Gilardoni, I.;Becca, F.;Marrazzo, A.;
2022-01-01
Abstract
Taking the clue from the modern theory of polarization [Rev. Mod. Phys. 66, 899 (1994)RMPHAT0034-686110.1103/RevModPhys.66.899], we identify an operator to distinguish between Z2-even (trivial) and Z2-odd (topological) insulators in two spatial dimensions. Its definition extends the position operator [Phys. Rev. Lett. 82, 370 (1999)PRLTAO0031-900710.1103/PhysRevLett.82.370], which was introduced in one-dimensional systems. We first show a few examples of noninteracting models where single-particle wave functions are defined and allow for a direct comparison with standard techniques on large system sizes. Then, we illustrate its applicability for an interacting model on a small cluster where exact diagonalizations are available. Its formulation in the Fock space allows a direct computation of expectation values over the ground-state wave function (or any approximation of it), thus, allowing us to investigate generic interacting systems, such as strongly correlated topological insulators.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
