# Interaction of two level systems in amorphous materials with arbitrary phonon fields.

## Abstract

To describe the interaction of the two-level systems (TLSs) of an amorphous solid with arbitrary strain fields, we introduce a generalization of the standard interaction Hamiltonian. In this model, the interaction strength depends on the orientation of the TLS with respect to the strain field through a 6 x 6 symmetric tensor of deformation potential parameters [R]. Taking into account the isotropy of the amorphous solid, we deduce that [R] has only two independent parameters. We show how these two parameters can be calculated from experimental data, and we prove that for any amorphous bulk material, the average coupling of TLSs with longitudinal phonons is always stronger than the average coupling with transversal phonons (in standard notations, {gamma}{sub l} > {gamma}{sub t}).

- Authors:

- Publication Date:

- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC); NATO

- OSTI Identifier:
- 940700

- Report Number(s):
- ANL/MSD/JA-57783

Journal ID: ISSN 1098-0121; TRN: US0807188

- DOE Contract Number:
- DE-AC02-06CH11357

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Phys. Rev. B; Journal Volume: 75; Journal Issue: 2007

- Country of Publication:
- United States

- Language:
- ENGLISH

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DEFORMATION; ISOTROPY; ORIENTATION; PHONONS; STRAINS

### Citation Formats

```
Anghel, D. V., Kuhn, T., Galperin, Y. M., Manninen, M., Materials Science Division, National Inst. for Physics and Nuclear Engineering, Univ. Jyvaskyla, Univ. Oslo, and Russian Academy of Sciences.
```*Interaction of two level systems in amorphous materials with arbitrary phonon fields.*. United States: N. p., 2007.
Web. doi:10.1103/PhysRevB.75.064202.

```
Anghel, D. V., Kuhn, T., Galperin, Y. M., Manninen, M., Materials Science Division, National Inst. for Physics and Nuclear Engineering, Univ. Jyvaskyla, Univ. Oslo, & Russian Academy of Sciences.
```*Interaction of two level systems in amorphous materials with arbitrary phonon fields.*. United States. doi:10.1103/PhysRevB.75.064202.

```
Anghel, D. V., Kuhn, T., Galperin, Y. M., Manninen, M., Materials Science Division, National Inst. for Physics and Nuclear Engineering, Univ. Jyvaskyla, Univ. Oslo, and Russian Academy of Sciences. Mon .
"Interaction of two level systems in amorphous materials with arbitrary phonon fields.". United States.
doi:10.1103/PhysRevB.75.064202.
```

```
@article{osti_940700,
```

title = {Interaction of two level systems in amorphous materials with arbitrary phonon fields.},

author = {Anghel, D. V. and Kuhn, T. and Galperin, Y. M. and Manninen, M. and Materials Science Division and National Inst. for Physics and Nuclear Engineering and Univ. Jyvaskyla and Univ. Oslo and Russian Academy of Sciences},

abstractNote = {To describe the interaction of the two-level systems (TLSs) of an amorphous solid with arbitrary strain fields, we introduce a generalization of the standard interaction Hamiltonian. In this model, the interaction strength depends on the orientation of the TLS with respect to the strain field through a 6 x 6 symmetric tensor of deformation potential parameters [R]. Taking into account the isotropy of the amorphous solid, we deduce that [R] has only two independent parameters. We show how these two parameters can be calculated from experimental data, and we prove that for any amorphous bulk material, the average coupling of TLSs with longitudinal phonons is always stronger than the average coupling with transversal phonons (in standard notations, {gamma}{sub l} > {gamma}{sub t}).},

doi = {10.1103/PhysRevB.75.064202},

journal = {Phys. Rev. B},

number = 2007,

volume = 75,

place = {United States},

year = {Mon Jan 01 00:00:00 EST 2007},

month = {Mon Jan 01 00:00:00 EST 2007}

}