The effect of a Zeeman magnetic field coupled to the spin of the electrons on the conducting properties of the disordered Hubbard model is studied. Using the determinant quantum Monte Carlo method,... Show moreThe effect of a Zeeman magnetic field coupled to the spin of the electrons on the conducting properties of the disordered Hubbard model is studied. Using the determinant quantum Monte Carlo method, the temperature- and magnetic-field-dependent conductivity is calculated, as well as the degree of spin polarization. We find that the Zeeman magnetic field suppresses the metallic behavior present for certain values of interaction and disorder strength and is able to induce a metal-insulator transition at a critical field strength. It is argued that the qualitative features of magnetoconductance in this microscopic model containing both repulsive interactions and disorder are in agreement with experimental findings in two-dimensional electron and hole gases in semiconductor structures. Show less
The effect of a Zeeman magnetic field coupled to the spin of the electrons on the conducting properties of the disordered Hubbard model is studied. Using the determinant quantum Monte Carlo method,... Show moreThe effect of a Zeeman magnetic field coupled to the spin of the electrons on the conducting properties of the disordered Hubbard model is studied. Using the determinant quantum Monte Carlo method, the temperature- and magnetic-field-dependent conductivity is calculated, as well as the degree of spin polarization. We find that the Zeeman magnetic field suppresses the metallic behavior present for certain values of interaction and disorder strength and is able to induce a metal-insulator transition at a critical field strength. It is argued that the qualitative features of magnetoconductance in this microscopic model containing both repulsive interactions and disorder are in agreement with experimental findings in two-dimensional electron and hole gases in semiconductor structures. Show less
Batrouni, G.G.; Rousseau, V.; Scalettar, R.T.; Rigol, M.; Muramatsu, A.; Denteneer, P.J.H.; Troyer, M. 2002
The understanding of the interplay of electron correlations and randomness in solids is enhanced by demonstrating that particle-hole ( p−h) symmetry plays a crucial role in determining the effects... Show moreThe understanding of the interplay of electron correlations and randomness in solids is enhanced by demonstrating that particle-hole ( p−h) symmetry plays a crucial role in determining the effects of disorder on the transport and thermodynamic properties of the half-filled Hubbard Hamiltonian. We show that the low-temperature conductivity decreases with increasing disorder when p−h symmetry is preserved, and shows the opposite behavior, i.e., conductivity increases with increasing disorder, when p−h symmetry is broken. The Mott insulating gap is insensitive to weak disorder when there is p−h symmetry, whereas in its absence the gap diminishes with increasing disorder. Show less
Denteneer, P.J.H.; Scalettar, R.T.; Trivedi, N. 1999
A variety of experiments have revealed several puzzling properties of hydrogen-impurity pairs. For example, H atoms passivate the electrical activity of some impurities, whereas they induce... Show moreA variety of experiments have revealed several puzzling properties of hydrogen-impurity pairs. For example, H atoms passivate the electrical activity of some impurities, whereas they induce electrical activity in others; they appear to tunnel around some impurities but not around others. We report first-principles pseudopotential-density-functional calculations for several hydrogen-impurity complexes and unravel the origins and intricacies of the rich behavior of H bound to different substitutional impurities in Si and Ge. Show less
